Apparatus and method for performing random access procedure in wireless communication system

Abstract

The present disclosure relates to performing a random access procedure in a wireless communication system, and an operation method of a terminal may comprise the steps of: receiving system information; acquiring information related to a random access channel (RACH) based on the system information; identifying the type of the available RACH preamble based on the transmission bandwidth of the terminal; selecting a RACH preamble based on the information and the type related to the RACH; and transmitting the selected RACH preamble through the RACH.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to an apparatus and method for performing a random access procedure 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 performing a random access procedure in a wireless communication system.

[0006] The present disclosure may provide an apparatus and method for transmitting a Random Access Channel (RACH) preamble in a wireless communication system.

[0007] The present disclosure may provide an apparatus and method for obtaining information related to RACH based on system information in a wireless communication system.

[0008] The present disclosure may provide an apparatus and method for transmitting a RACH preamble based on a transmission bandwidth and a required bandwidth of a RACH signal in a wireless communication system.

[0009] The present disclosure may provide an apparatus and method for puncturing at least one sample in a RACH sequence having a designated length in a wireless communication system.

[0010] The present disclosure may provide an apparatus and method for leaving at least one resource element (RE) blank among REs within a transmission bandwidth and mapping a RACH preamble in a wireless communication system.

[0011] The present disclosure may provide an apparatus and method for determining a location to map a RACH sequence sample within a transmission bandwidth in a wireless communication system.

[0012] The present disclosure may provide an apparatus and method for determining a RACH sequence length based on a transmission bandwidth in a wireless communication system.

[0013] The present disclosure may provide an apparatus and method for determining a new format of a RACH sequence based on a transmission bandwidth in a wireless communication system.

[0014] The present disclosure may provide an apparatus and method for limiting the use of some RACH sequences based on transmission bandwidth in a wireless communication system.

[0015] The technical objectives to be achieved in the present disclosure are not limited to the above contents, and those skilled in the art in the field to which the technical configuration of the present disclosure is applied may consider other technical objectives not mentioned from the embodiments of the present disclosure 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 system information; obtaining information related to a random access channel (RACH) based on the system information; identifying a type of available RACH preamble based on a transmission bandwidth of the terminal; selecting a RACH preamble based on the information and type related to the RACH; and sending the selected RACH preamble through the RACH.

[0018] As an example of the present disclosure, a method for operating a base station in a wireless communication system may include: transmitting system information including information related to a random access channel (RACH); and receiving a RACH preamble from a terminal through the RACH. The RACH preamble may belong to a type of available RACH preambles based on a transmission bandwidth of the terminal.

[0019] As an example of the present disclosure, a terminal in a wireless communication system may include a transceiver and a processor coupled to the transceiver. The processor may be configured to: receive system information; obtain information related to a random access channel (RACH) based on the system information; identify the type of available RACH preambles based on a transmission bandwidth of the terminal; select a RACH preamble based on the information and type related to the RACH; and send the selected RACH preamble through the RACH.

[0020] As an example of the present disclosure, a base station in a wireless communication system may include a transceiver and a processor coupled to the transceiver. The processor may be configured to: send system information including information related to a random access channel (RACH); and receive a RACH preamble from a terminal via the RACH. The RACH preamble may belong to a type of available RACH preambles based on a transmission bandwidth of the terminal.

[0021] As an example of the present disclosure, a communication device may include at least one processor and at least one computer memory, the at least one computer memory being coupled to the at least one processor and storing instructions that, when executed by the at least one processor, indicate operations. These operations may include: receiving system information; obtaining information related to a random access channel (RACH) based on the system information; identifying the type of available RACH preambles based on a transmission bandwidth of the communication device; selecting a RACH preamble based on information and type related to the RACH; and transmitting the selected RACH preamble via the RACH.

[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 that can be executed by a processor. The at least one instruction may control a device to: receive system information; obtain information related to a random access channel (RACH) based on the system information; identify the type of available RACH preambles based on a transmission bandwidth of the device; select a RACH preamble based on the information and type related to the RACH; and transmit the selected RACH preamble through the RACH.

[0023] The above-mentioned aspects of the present disclosure are only a part of the exemplary embodiments of the present disclosure, and based on the detailed description of the present disclosure, those skilled in the art can derive and understand various embodiments reflecting the technical features 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, performance degradation can be minimized while maintaining cell coverage in a narrowband.

[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 A 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 may 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 An example of a random access channel (RACH) preamble based on a long sequence is illustrated.

[0037] Fig. 9 An example of a RACH preamble based on a short sequence is illustrated.

[0038] Fig.10 An example of interference for a short sequence is illustrated.

[0039] Fig.11 An example of a sequence whose center is aligned with the center RE is illustrated.

[0040] Fig.12 An example of a starting RB of a RACH sequence is illustrated.

[0041] Fig.13 An example of a process of transmitting a RACH preamble for random access in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0042] Fig.14An example of a process of transmitting a partial or full sequence sample of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0043] Fig.15 An example of a process of mapping a partial sequence sample of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0044] Fig.16 An example of a process of aligning sequence samples of a RACH preamble within a transmission bandwidth in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0045] Fig.17 An example of a process of determining a RACH preamble sequence sample length in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0046] Fig.18 An example of a process of repeatedly mapping RACH preamble sequence samples in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0047] Fig.19 An example of a process of determining a starting RB for mapping a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0048] Fig. 20 An example of a process of mapping sequence samples based on usage restriction of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated.

[0049] Fig.21 An example of a process of receiving a RACH preamble for random access in a wireless communication system according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0050] 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 with the corresponding structures or features of another embodiment.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 invention are applicable to systems applied after the 3GPP 5G NR system and are not limited to a specific system.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] Overall system

[0067] 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 a representation of an example representing a 5G RAT.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] Figure 2 An example of a wireless device applicable to the present disclosure is illustrated.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] For example, the device may be an XR device such as an HMD, a head-up display (HUD) provided in a vehicle, a television, 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.

[0084] 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.

[0085] 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.

[0086] Figure 3 A frame structure in a wireless communication system to which the present disclosure can be applied is illustrated.

[0087] 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.

[0088] 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.

[0089] [Table 1]

[0090] μ <![CDATA[Δf=2 μ ·15[kHz]]]> CP 0 15 normal 1 30 normal 2 60 Normal, Extended 3 120 normal 4 240 normal

[0091] 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, bandwidths greater than 24.25GHz are supported to overcome phase noise. The NR band is defined as two types of frequency ranges (FR1, FR2). FR1 and FR2 can be configured according to Table 2 below. In addition, FR2 can mean millimeter wave (mmW).

[0092] [Table 2]

[0093] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0094] 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 =10ms duration radio frame. 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 All terminals cannot perform transmission and reception at the same time, which means that not all OFDM symbols of a downlink slot or uplink slot are available. [Table 3] shows the number of OFDM symbols per 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.

[0095] [Table 3]

[0096]

[0097] [Table 4]

[0098]

[0099] 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 can be included in 1 subframe is as defined in Table 3 or Table 4. In addition, a micro slot may include 2, 4, or 7 symbols or more or less. Regarding physical resources in the NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc. may be considered. Hereinafter, the physical resources that may be considered in the NR system will be described in detail.

[0100] 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.

[0101] 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.

[0102] Figure 4 A resource grid in a wireless communication system to which the present disclosure may be applied is illustrated.

[0103] 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. Here, 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.

[0104] Point A plays the role of a common reference point for the resource block grid and is obtained as follows.

[0105] -OffsetToPointA for the primary cell (PCell) downlink represents the frequency offset between point A and the lowest subcarrier of the lowest resource block overlapping the SS / PBCH block used by the terminal for initial cell selection. It is expressed in resource blocks, assuming a subcarrier spacing of 15kHz for FR1 and 60kHz for FR2.

[0106] -absoluteFrequencyPointA represents the frequency position of point A, as expressed in absolute radio frequency channel number (ARFCN).

[0107] 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 in Equation 1 below.

[0108] [Equation 1]

[0109]

[0110] 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 equation 2.

[0111] [Equation 2]

[0112]

[0113] is the common resource block where the BWP starts relative to common resource block 0.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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).

[0118] 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 procedure 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.

[0119] Figure 7 A physical channel used in a wireless communication system to which the present disclosure may be applied and a general signal transmission and reception method using the physical channel are illustrated.

[0120] 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.

[0121] 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.

[0122] 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).

[0123] 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.

[0124] The terminal that has 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.

[0125] 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.

[0126] Specific embodiments of the present disclosure

[0127] The present disclosure relates to a technique for performing a random access procedure in a wireless communication system. Specifically, the present disclosure relates to a technique for sending a RACH preamble in a wireless communication system, and more particularly to a technique for mapping a RACH preamble to a resource in an environment with limited bandwidth.

[0128] 5G NR provides services mainly through major technologies such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive Internet of Things (mIoT). mIoT is a communication method that is optimized based on small size and low power to reduce power consumption, unlike carrier aggregation (CA) that requires high performance and maximum throughput speed transmission.

[0129] In 5G NR, there are three main technologies, URLLC, eMBB and mIoT, and a hybrid technology of these three technologies may be provided. In 3GPP Release 17, a new device type that targets smart factories or wearable devices and requires low power and a certain level of transmission rate is called a reduced performance terminal, i.e., reduced capability (Redcap) UE. Here, unlike previous types, Redcap UE or Redcap terminal uses a narrow spectrum or narrow bandwidth as frequency resources. The predetermined frequency bandwidth used for a specific channel or signal transmission may not be fully used by the Redcap terminal, depending on how narrow the spectrum or bandwidth used is.

[0130] In the uplink case, the flexibility of using only available frequency bands for most signals and channels is supported. However, in 5G NR, the frequency resource bandwidth of the RACH preamble is not flexibly defined but is defined in a fixed manner. In the same frequency band, when the subcarrier spacing (SCS) is 30kHz, the frequency area occupied by a single resource element (RE) is larger than when the SCS is 15kHz. Therefore, a considerable portion of the frequency resources of the RACH preamble are not utilized.

[0131] The RACH preamble has a sequence form, and each of the sequence samples is mapped to each RE in the frequency region. Here, if the frequency region becomes smaller, the number of available REs may also decrease. For example, if there are 100 PRACH preamble sequence samples and there are 90 REs in the current available frequency bandwidth, 90 sequence samples can be sent, but 10 sequence samples cannot be sent. Since the previous general terminal uses a frequency region of up to 100MHz according to FR1, the number of available REs is greater than the number of PRACH sequence samples, which does not cause significant problems in the transmission of the RACH preamble. However, the Redcap terminal uses a frequency region as small as 3MHz or 5MHz, and the number of available REs is less than the number of PRACH sequence samples, so it may be that some PRACH sequence samples cannot be sent. At this time, due to performance degradation, the service coverage area of ​​PRACH may be reduced. As a result, during the RACH process, the probability of occurrence of PRACH reception errors in Message1 becomes higher. Accordingly, in the case where the number of available REs is small and puncturing is inevitable, it is very important to find a solution to minimize performance degradation by efficiently sending the RACH preamble. In the following description, BW (bandwidth) may be understood to be equivalent to BWP (bandwidth part).

[0132] Therefore, the present disclosure provides a technology for sending a channel or signal (e.g., a preamble) within the actual available bandwidth of a Redcap terminal when the required bandwidth of the channel or signal is wider than the given bandwidth of the Redcap terminal. If the bandwidth required for using a specific signal or channel is wider than the actual available bandwidth of the Redcap terminal, part of the information will be punctured or lost, which may cause performance degradation problems. Therefore, the present disclosure will provide various methods for minimizing or compensating for performance degradation.

[0133] Generally, PRACH is divided into a long sequence and a short sequence. The long sequence includes 839 sequence samples, and the short sequence includes 139 sequence samples. Therefore, in a frequency band, 893 or more REs are required to send a long sequence, and 139 or more REs are required to send a short sequence.

[0134] In the case of a Redcap terminal, the available bandwidth may be narrower than 100MHz. That is, a Redcap terminal may use a 5MHz bandwidth or a bandwidth narrower than 5MHz. In this case, as shown in Table 5 below, the specification defines the maximum number of available resource blocks (RBs). Table 5 shows the maximum number of available RBs according to bandwidth and subcarrier spacing (SCS).

[0135] [Table 5]

[0136]

[0137] Here, in the case of using a long sequence including 839 samples, one RE has a frequency interval of 1.25kHz or 5kHz, so that 893 samples can be fully included in 5MHz. However, even if a long sequence is used, if a dedicated bandwidth allocated within 3MHz is used, since one RE frequency interval of 5kHz SCS is wider than 1.25kHz, the number of available REs within 3MHz may not be sufficient for RACH preamble transmission. In addition, for a short sequence using 15kHz or 30kHz SCS, 132 of the 139 samples can be sent through 11 RBs (i.e., 12×11=132REs), but the remaining 7 samples are not sent.

[0138] Therefore, for RACH preamble transmission requiring a predetermined number of REs, the present disclosure aims to illustrate a method of mapping a sequence to a limited number of REs and a method of solving related problems. For example, the present disclosure proposes a method of indicating the number of RBs to be used through SIB.

[0139] PRACH can be divided into Figure 8 The RACH preamble code based on the long sequence is exemplified, or divided into: Fig. 9 An example of a short sequence based RACH preamble. Figure 8An example of a long sequence based random access channel (RACH) preamble is shown. Figure 8 , the long sequence-based RACH preamble includes a sequence of length 839 and has multiple formats (e.g., formats 0, 1, 2, 3). Here, each of these formats can be applied based on coverage and / or whether there is a high-speed situation. For example, for LTE coverage, a RACH preamble of format 0 can be used, while for a high-speed situation, a RACH preamble of format 3 can be used.

[0140] Fig. 9 An example of a RACH preamble based on a short sequence is illustrated. Fig. 9 , the RACH preamble based on the short sequence includes a sequence of length 139 and has multiple formats (A1, A2, A3, B1, B2, B3, B4, C0, C2). The short sequence can be used when the SCS is 15Kz or 30kHz. When the SCS is 15Kz or 30kHz, the total number of REs in the 5MHz bandwidth is greater than the number of sequence samples 139, so the above problem does not occur.

[0141] The SCS using a short sequence is 15kHz or 30kHz, and is much larger than the SCS using a long sequence. Therefore, since REs occupy a larger frequency area, unlike long sequences, there is a problem that only a small number of REs are available in a narrow band. Therefore, it may happen that the terminal cannot send 139 samples in a given frequency band. For example, referring to Table 5, when the SCS is 30kHz, 11 RBs can be used in a 5MHz bandwidth. Here, if another terminal sends PUSCH in an adjacent frequency band to the frequency band where the RACH preamble is sent, the following may occur: Fig.10 The interference shown.

[0142] Fig.10 An example of interference with a short sequence is shown. Fig.10 , showing that sample #0 interferes with the adjacent frequency band of sample #140. Therefore, it is desirable to allocate as many gaps as 1 or 2 REs at the front end of the first RB in the frequency region and place sequence samples starting from the next RE. In addition, some REs at the rear end of the last RB in the frequency region may also be allocated as gaps. REs allocated as gaps may not be filled with sequence samples. This can prevent Fig.10 That is, in order to stably send the RACH preamble code, it is necessary to ensure that the number of REs should be greater than the sum of the number of specific sequence samples (= number of REs) and the number of REs allocated as gaps at the front end and / or the back end. To this end, the parameters can be defined as shown in Table 6 Table 6 shows the RE offset for transmitting PRACH.

[0143] [Table 6]

[0144]

[0145] [Table 6] shows the offset The offset Indicates how many REs need to be vacated at the front end of the first RB in the frequency region allocated according to SCS to place the PRACH sequence. According to the implementation method, some REs at the back end of the last RB can also be vacated. According to Table 6, for the case of using a short sequence including 139 samples, the offset is defined as 2. This may mean that when a short sequence including 139 samples is used, the first 2 REs should be left blank in the first RB. If 1 RE is left blank or no RE is left blank, interference with PUSCH may occur as described above, but the base station can perform appropriate scheduling so that PUSCH transmission is not performed in an adjacent frequency band at the corresponding transmission time.

[0146] Various embodiments of operating the PRACH sequence when the number of available REs excluding the REs that need to be vacated at the two boundaries of the frequency band is less than the number of REs required to send the PRACH sequence will be described below. In the case of using a BW(P) wider than 5 MHz, the following embodiments can be applied not only to a short sequence including 139 samples, but also to other sequences (e.g., a long sequence including 839 samples).

[0147] Implementation #1: Method for mapping PRACH sequence and offset RE within available PRB

[0148] Embodiment 1-1: Method of puncturing the same number of REs in two RBs at two edges within a frequency band

[0149] For example, in the case of transmitting 139 samples of a short sequence through 11 PRBs at 30 kHz, since the 11 PRBs include 132 REs, 7 of the 139 samples may be punctured. Additionally, to mitigate interference, the terminal leaves the same number of REs (e.g., 1 or 2 REs) empty at both boundaries and maps the sequence samples to the remaining REs. In this case, if 1 RE is vacated at each of the two boundaries, 2 of the 139 samples are additionally punctured. That is, if 1 or 2 REs are vacated at the two boundaries, 9 or 11 of the 139 samples are not transmitted, and thus PRACH performance degradation may be more severe than when 7 samples are punctured. However, in the case of vacating REs at both boundaries of the frequency band, interference with another channel in an adjacent frequency band can be reduced. Compared to sending a total of 139 samples, the performance degradation when 1 RE is vacated at the two boundaries is less severe than the performance degradation when 2 REs are vacated at the two boundaries. However, the interference effect on the adjacent band when 1 RE is vacated at the two boundaries may not be greater than the interference effect on the adjacent band when 2 REs are vacated at the two boundaries. For reference, as shown in Table 6, 2 REs may be the minimum offset value that can eliminate interference with the adjacent band.

[0150] Implementation 1-2: Method for puncturing different numbers of REs in RBs at two boundaries

[0151] For example, the terminal may leave 2 REs empty at the front end of the first RB and leave 3 REs empty at the rear end of the last RB. As another example, the terminal may leave 1 RE empty at the front end of the first RB and select to leave the remaining REs empty at the rear end of the last RB. As another example, the terminal may leave 1 RE empty at the rear end of the last RB and leave the remaining REs empty at the front end of the first RB.

[0152] Alternatively, according to Table 6, the terminal may leave 2 REs empty at the front end of the first RB and only leave one final RE empty at the last RB. At this time, K1 is used as is, but only the minimum number of REs (i.e., 1 RE) is left empty to minimize puncturing and minimize high-band interference.

[0153] Embodiment 1-3: Method of leaving the front RE and the rear RE blank in only one of the two RBs at two boundaries

[0154] According to this method, one of the two RBs at the two boundaries can be fully used without vacating the RB. For example, only 1 RE or 2 REs can be vacated in the first RB. Alternatively, the first RB may not be vacated, but the sequence samples are mapped starting from the first RE of the first RB, and the last 1 or last 2 REs are vacated in the last RB. Therefore, if at least 1 RE is vacated in only one of the two RBs, the number of punctured samples may be less than the number of punctured samples in the above-mentioned embodiments 1-1 and 1-2. However, when at least 1 RE is vacated in only one of the two RBs, interference may be concentrated on one side of the frequency band. Accordingly, high-level signaling (e.g., SIB, RRC signaling) may indicate in advance which RB will vacate at least 1 RE.

[0155] Implementation #2: Method for determining the mapping start position of the PRACH sequence

[0156] According to Embodiment 2, REs at two boundaries that can be used to reduce interference with adjacent frequency bands are not vacated.

[0157] Implementation 2-1: Method for mapping a sequence starting from the first RE

[0158] For example, the terminal may start mapping the sequence from the first RE of the first RB. In this case, the sequence may start from the first RE of the first RB, and the rear of the sequence may be punctured.

[0159] Embodiment 2-2: Method for mapping by aligning the center of a sequence with a central RE

[0160] For example, Fig.11 As shown, the terminal may perform mapping by aligning the center 1101 of the sequence with the center RE among the REs in the frequency band. Fig.11 An example is shown where the center of the sequence is aligned with the center RE. At this time, both ends of the sequence may be punctured.

[0161] In the case of implementation #2, the possibility of interference with the adjacent area of ​​the used frequency band is higher than that in implementation #1. It can be set to 0 or a negative value. That is, implementation #2 needs to bear a certain degree of interference, but minimizes the number of punctured samples in the PRACH sequence to 7, thereby minimizing the performance degradation of the PRACH itself.

[0162] Implementation #3: Method for determining different length values ​​of PRACH sequence

[0163] Sequences of different lengths from the sequence length determined based on the definition in the specification can be used. For example, the different lengths can be determined as a maximum prime number that is less than the required sequence length. Usually to prevent correlation, the sequence length can be set to a prime number with only two factors (i.e., 1 and the number itself).

[0164] Implementation 3-1: Reuse Table 6 as in Implementation #1 Value Method

[0165] When the sequence length is shorter than the required sequence length and is reused as is In the case of a value of , the sequence length can be set to the maximum prime number that minimizes puncturing. For example, when the number of available REs is 132 and In the case of 2, the sequence length can be determined to be 127, which is less than the required sequence length of 132 by subtracting The maximum prime number among the prime numbers of 130 obtained by the value. When the sequence length is 127, the terminal can leave 2 REs empty at the front end of the first RB and leave 3 REs empty at the back end of the last RB. That is, Can be used without modification.

[0166] Implementation 3-2: Using Table 6 as Implementation #1 Value Method

[0167] Sequence length can be set to the maximum prime number among the prime numbers less than the required sequence length. For example, when the available RE quantity is 132, the sequence length can be determined as 131, which is the maximum prime number among the prime numbers less than the required sequence length 132. When the sequence length is 131, the terminal can leave 2 REs at the front end of the first RB and use all REs of the last RB. In this case, 1 of the 131 samples may be punctured.

[0168] Implementation 3-3: Use in the above Implementation 3-2 How to set

[0169] For example, when the sequence length is 131, the terminal can leave 1 RE blank at the front of the first RB and map the sequence to all remaining REs. In this case, the sequence including 131 samples can be sent without puncturing, and the interference at one end of the frequency band can be reduced. However, interference may occur at the other end of the frequency band.

[0170] Implementation 3-4: In the above implementation 3-2, the two sides are applied Methods

[0171] For example, when the sequence length is 131, the terminal may leave blank the first RE of the first RB and the last RE of the last RB. In this case, frequency interference of PUSCH transmission can be reduced, but 1 of 131 samples of the RACH preamble code may be punctured.

[0172] For the above-mentioned implementation modes 3-1 to 3-4, various applications can be implemented through high-layer signaling.

[0173] In the above-mentioned embodiments, the present disclosure illustrates 11 RBs under 30kHz SCS of a short sequence. However, the above-mentioned embodiments may also be applied to long sequences and / or short sequences when the bandwidth is equal to or narrower than 5MHz. Additionally, for example, in the case of a long sequence of length 839 in a 3MHz bandwidth, the number of sequence samples may be greater than the total number of available REs in format 3 using 5kHz SCS. In this case, the following may be applied: a method of leaving some REs blank at both boundaries of the frequency band to reduce interference and protect other channel users (as in the above-mentioned embodiment #1); a method of using all REs to minimize puncturing on sequence samples (as in embodiment #2); or a method of modifying the sequence length to another length equal to the maximum prime number among prime numbers less than a predetermined sequence length, and then sending a PRACH with the modified sequence length (as in embodiment #3).

[0174] In the case where the RACH preamble sequence cannot be completely mapped to the REs within the available bandwidth, another preamble sequence with a length that is a maximum prime number less than the specified preamble sequence length may be sent. There may be multiple transmittable sequences with a prime length within the reduced bandwidth, but it is desirable to use the sequence with the maximum prime length.

[0175] Implementation #4: Method for compensating for performance degradation caused by PRACH sequence puncturing

[0176] According to some methods of the above embodiments, a portion of the RACH preamble sequence may be punctured. In the case where a portion of the RACH preamble sequence is punctured, the coverage may be reduced compared to when the RACH preamble sequence is not punctured. Therefore, the present disclosure proposes an embodiment that can compensate for the performance degradation caused by such coverage reduction. Fig. 9 The shaded area in the middle represents PRACH transmission in one frequency region. Fig. 9 It is shown that PRACH transmission is repeated in time. That is, the RACH preamble includes repetition of the sequence. The following Table 7 shows the number of repetitions according to each PRACH format.

[0177] [Table 7]

[0178] Format Repetitions 0 0 1 1 2 3 3 3 A1 1 A2 3 A3 5 B1 1 B2 3 B3 5 B4 11 C0 0 C2 3

[0179] In the case where the sequence is punctured according to the above embodiment, the performance may be degraded. In this case, the terminal may compensate for the performance degradation caused by puncturing by applying a greater number of repetitions than the number of repetitions defined for each format in Table 7 when sending PRACHT.

[0180] Embodiment 4-1: A new PRACH format with a greater number of repetitions than the existing number of repetitions may be defined. For example, formats 5, 6, and 7 may be newly defined for long sequences, and formats A4, A5, B5, C3, and C4 or formats Dx and Ex may be newly defined for short sequences.

[0181] Implementation 4-2: While not defining a new PRACH format and retaining each form of the existing PRACH format, the number of repetitions of some existing PRACH formats may be increased. For example, the terminal may increase the number of repetitions of some formats by adding a specific number to the number of repetitions or multiplying the number of repetitions by a multiple. In this case, the increased specific number or multiple may be indicated to the terminal in advance through high-layer signaling (e.g., SIB, RRC signaling) or other signaling.

[0182] Implementation #5: Other RE mapping methods for PRACH sequences

[0183] According to implementation #5, an offset may be applied to the first RB.

[0184] The above-mentioned implementation #1 to implementation #4 are based on Fig.12 Case A 1210 is shown for description. Fig.12 An example of the starting RB of a PRACH sequence is shown. Fig.12 , case A 1210 is the case of using 11 RBs in a 5MHz bandwidth. However, from the perspective of the base station, the use of 5MHz BW(P) is expected to be rare. Therefore, when configuring PRACH related resources, 12 RBs are usually allocated based on 30kHz SCS. When 12 RBs are allocated, all 139 samples of the short sequence can be sent. From the perspective of the base station, if the channel bandwidth is equal to or wider than 5MHz (such as Fig.12 In case B 1220), the remaining 11 PRBs except the first RB may be configured to be used. This is intended to coexist with the existing PRACH configuration because the base station can use 12 PRBs. In this case, whether to leave the first RB blank may be preset through SIB signaling. The above implementation is also applicable to case B 1220.

[0185] Therefore, in the scenario where the above implementation is applied to the PRACH sequence, the sequence sample may start from the first RB or the second RB. For example, in implementation #2, the sequence sample is not mapped from the first RE of the first RB, but is mapped as follows: Fig.12 As shown in case B (x520), the RB additional offset and The position where the value is mapped starts. Thus the starting sample of the sequence may become different.

[0186] That is, which RB among the 12 RBs in the frequency band starts mapping the 30kHz SCS sequence can be determined by high-level signaling, and within the RB thus determined, the RE that will start sample mapping can be determined by Sure. is the sequence offset of PRACH and can be set in symbol units. In addition, assuming that the value indicated by the high-level signaling indicating the RB position mapped to the sequence among the 12 PBs in the frequency band is X, then X is the offset of PRACH PRB and can be set in RB units. X can be 0 or 1.

[0187] X and / or It can be sent to the terminal in advance through SIB. Alternatively, X and / or Set to a specific value for a specific terminal (e.g., Redcap terminal). X and / or An example of specific signaling is described below:

[0188] Example A: and X can be delivered to the terminal via high-level signaling. In this case, and X are operated on separately.

[0189] Example B: X may not be used and the 12 symbols may be included in of candidate values.

[0190] Example C: Not using [Table 6] Value, and indicated by signaling such as SIB value.

[0191] Embodiment #6: Restricting the use of sequences with a specific form when PRACH is applied to 5 MHz or narrower spectrum Methods

[0192] In the case of using a spectrum band within 5MHz, the sequence exceeds the corresponding bandwidth according to the SCS. Therefore, available sequences that do not exceed the bandwidth can be predefined. Alternatively, the use of sequences that exceed the bandwidth can be restricted by using RRC, SIB, etc. For example, in the case where the PRACH length of a long sequence or a short sequence defined in the existing 5G NR exceeds the number of available PRBs in the narrowband width, a specific PRACH format that does not use the corresponding PRACH sequence can be predefined. Alternatively, in the higher layer, it can be configured not to use a specific PRACH format. Therefore, the terminal may not expect to use a specific SCS, a specific PRACH format, or a PRACH configuration index corresponding thereto. In this case, the implementation or operation of the terminal is advantageously simplified.

[0193] Embodiment 6-1: A RACH preamble code including a short sequence having an SCS of 30 kHz or greater or a specific SCS or greater may not be used. For example, in an environment such as a railway or subway, various SCSs may not be required for services. Therefore, when operating using an ultra-narrowband network of 5 MHz or less, it may be convenient to limit the use of RACH preamble codes that use a specific SCS that significantly exceeds the bandwidth. The sequence may be punctured or a new form of sequence may be defined in a specific form, but as shown in this embodiment, by excluding RACH preamble codes that use a specific SCS in a specific frequency band, the system can operate without major modifications to the specification.

[0194] A short sequence can be specified to be used only in a specific SCS. A short sequence can be predefined to use only a 15kHz SCS. Alternatively, the base station can exclude sending SCS parameters in a higher layer (e.g., RRC). In the absence of receiving this parameter, the terminal can recognize that 15kHz is the only available SCS. Therefore, the signaling overhead can be reduced. According to another embodiment, when the SCS of the BWP is equal to or wider than 30kHz, short sequences using 5kHz or other SCSs can be restricted to not be used. According to another embodiment, for each case of a specific situation (e.g., a BWP size that is too small), it can be defined that the short sequence is not used at all.

[0195] Embodiment 6-2: The RACH preamble code including the long sequence of 5kHz SCS may not be used. In the case where the specified bandwidth is as narrow as 3MHz, the PRACH using the long 5kHz sequence may be restricted as the case may be. In this case, the restriction may be applied without major modifications to the specification. Alternatively, it may be specified that the long sequence is not used for all SCSs and all formats. According to another embodiment, when the SCS of the BWP is equal to or wider than 30kHz, the long sequence using 5kHz or other SCS may be restricted to not be used.

[0196] Embodiment 6-3: For a specific service using a narrow spectrum bandwidth, a format not exceeding the existing PRACH sequence length and a corresponding PRACH configuration index and SCS may be predefined. Therefore, the terminal may not expect the base station to configure the PRACH configuration index and SCS.

[0197] Implementation 6-4: In a high layer, for a spectrum within 5 MHz, it may be configured to exclude the use of a specific implementation among the above implementations. For example, depending on the bandwidth in the spectrum, it may be configured in a high layer whether to exclude the use of the puncturing, rate matching, and new sequences proposed in the above implementations, or the SCS, sequence, and format defined in the specification. In this case, configuration information that limits settings related to operation within a specified bandwidth (e.g., SCS, PRACH format, long sequence, short sequence) may be signaled.

[0198] Implementation 6-5: When the sequence length set according to SCS and PRACH for a narrow bandwidth of the corresponding spectrum in a higher layer (for example, RRC) exceeds the number of available PRBs in the bandwidth, the puncturing method, rate matching method or method of adjusting the number of repetitions in the above implementation can be applied in the terminal.

[0199] Embodiment 6-6: For the case where the preamble index is signaled in RRC, additional parameters may be defined for narrow bandwidth (eg, BWP ≤ 5 MHz) separately from signaling the existing PRACH index.

[0200] In the PRACH related configuration, configuration information including RACH related parameters for narrow bandwidth may be sent. For example, RACH related parameters for narrow bandwidth may indicate the preambles available in an environment using narrow bandwidth. That is, at least a portion of the preamble format available under normal circumstances may be specified for narrow bandwidth. According to an embodiment, the parameter may be signaled via SIB. If the parameter is not received, the format of the existing PRACH configuration may be used. The parameter may be used for additional signaling of the BWP that does not exceed the bandwidth and is only applied to terminals with limited bandwidth usage.

[0201] Additional parameters may be set in a separate initial BWP. In the case where the separate initial BWP exceeds the bandwidth range of the corresponding BWP of the PRACH configuration format, the separate initial BWP is not used, and the legacy initial BWP may be used. If a preamble format that exceeds the BWP bandwidth range is configured in the legacy initial BWP, the corresponding cell may be identified as a barred cell.

[0202] Embodiment 6-7: In the case where there are not enough frequency resources in a specific bandwidth to map the preamble code sequence of PRACH, the preamble code format of the corresponding index may not be used. If the base station is configured with the corresponding index, the following operations may be performed. For a long sequence, if the sequence length exceeds the bandwidth limit, the terminal may use a long sequence of a PRACH format of another sequence. For a short sequence, if the sequence length exceeds the bandwidth limit, the terminal may use a short sequence of a PRACH format of another sequence. In the case where the PRACH sequence length used for 2-step RACH exceeds the bandwidth limit, the terminal may fall back to 4-step RACH instead of using 2-step RACH. In the case where the length of a long sequence or a short sequence exceeds the bandwidth limit, the terminal may regard the corresponding cell as a prohibited cell, not attempt PRACH in the cell, and search for another cell.

[0203] Embodiment 6-8: In case the preamble sequence is larger than the BWP or the bandwidth of the channel, some guard bands or PRBs of adjacent PRB bands may be used. For example, in case of 30kHz SCS with 5MHz BWP, 11 PRBs may be used. Here, sending a short sequence requiring 12 PRBs may not cause any major problems. Therefore, additional PRBs may be ensured in the guard band. However, interference issues may arise.

[0204] In this case, the configuration related to the number of PRBs added and which PRB to add can be sent via RRC signaling. For example, if only 1 PRB is added, it can be specified whether to add it in the lowest protection band or the highest protection band. The indication of additional PRB allocation can be sent via RRC signaling or higher layer signaling.

[0205] If 2 or more PRBs are additionally allocated in the guard band or adjacent sideband, and these 2 or more PRBs are only allocated on one side of the channel bandwidth, interference problems may arise. Therefore, it is beneficial to choose to additionally allocate PRBs in a distributed manner on both sides of the channel bandwidth to solve the interference problem. The indication of the selected position of the above PRBs can be signaled in the higher layer.

[0206] The implementation of allocating additional PRBs in a portion of the corresponding guard band can also be applied to the case where the BWP is limited and can also be applied to the case where the channel bandwidth is set to a narrowband. That is, additional PRBs can be used in the adjacent guard band of the channel bandwidth.

[0207] As described above, the preamble sequence may be transmitted by further using resources within the guard band. Here, according to the channel bandwidth, there may be several PRBs or tens of PRBs on each side of the guard band.

[0208] Embodiment 6-9: In the case where a specific preamble sequence exceeds the BWP or bandwidth, the PRB can be reallocated by using an SCS that is less than the specified SCS. For example, in the case of a short sequence using a 30kHz SCS, the PRB can be processed by using a 15kHz SCS. Additionally, the terminal can reallocate the PRB of the corresponding time slot and expect to perform scheduling so that there is no other uplink transmission in the time slot except the RACH preamble. As another example, in the case of a long sequence using a 5kHz SCS, the PRB can be processed by using a 1.25kHz SCS. Additionally, the terminal can reallocate the PRB of the corresponding time slot and expect to perform scheduling so that there is no other uplink transmission in the time slot except the RACH preamble.

[0209] In terms of reducing development costs as well as efficiency, from the perspective of mIoT rather than eMBB, it is expected that Redcap devices (such as wearable devices) with performance of about 10Mbps to 20Mbps will be activated. Here, services may not be provided primarily in the wide bandwidth of 5G eMBB, but in the narrow bandwidth of narrowband, and Redcap devices may be the primary target of such services. In this case, from the perspective of PRACH, Redcap devices may not be able to use the required frequency band compared to traditional broadband devices. Therefore, for situations where such PRACH puncturing occurs on a sequence, the present disclosure proposes a method for providing services with appropriate coverage while minimizing performance degradation. Therefore, even in narrowband, it is expected that the cell coverage performance expected of traditional PRACH can be retained, and low-cost and efficient Redcap services can be provided.

[0210] Fig.13 An example of a process of transmitting a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.13 A method of operating a terminal is illustrated.

[0211] Reference Fig.13 In step S1301, the terminal receives system information from the base station. For example, the terminal may receive a master information block (MIB) and at least one system information block. Fig.13Not shown, but before this step, the terminal may receive a synchronization signal block (SSB) including at least one synchronization signal through a cell search operation and obtain synchronization with the base station. The terminal may obtain information for accessing the base station and information for performing subsequent communication processes with the base station. Here, the system information may include information related to RACH. For example, the information related to RACH may indicate and / or include at least one of the following: the number and / or position of REs to be punctured in the PRB used for RACH transmission, an RB offset indicating the RB to be transmitted in the RACH transmission among the RBs within the transmission bandwidth, a sequence format restricted in use, whether a new sequence format is used, and rate matching information.

[0212] In step S1303, the terminal determines the RACH preamble based on the system information and the transmission bandwidth. According to an embodiment, the terminal may identify the information related to the RACH based on the system information, identify the type of the available RACH preamble based on the transmission bandwidth, and then determine the RACH preamble based on the information related to the RACH and the type of the PRACH preamble. Here, the transmission bandwidth means the bandwidth available to the terminal. Based on the transmission bandwidth, the terminal may identify a long preamble including 839 samples or a short preamble including 139 samples as an available preamble type. For example, in the case where the transmission bandwidth corresponds to a narrow bandwidth of 5MHz or less, the terminal may identify the availability of the short preamble, and in the case where the transmission bandwidth corresponds to a bandwidth wider than 5MHz, the terminal may identify the availability of the long preamble. For example, for a transmission bandwidth less than 5MHz, a short preamble format using a 15kHz SCS and a long preamble format using a 1.25kHz SCS may be supported. For example, based on the information related to the RACH and the type of the PRACH preamble code, the terminal can determine the RACH preamble code by determining at least one of the following items: the number of REs to be vacated within the transmission bandwidth, the sequence mapping position, the format of the sequence, the number of sequence samples, the length of the sequence, and the number of samples to be punctured.

[0213] In step S1305, the terminal transmits the determined RACH preamble through RACH. The terminal transmits the RACH preamble to the base station by using RE within the transmission bandwidth. That is, the terminal may map the samples included in the RACH preamble to RE within the transmission bandwidth, perform OFDM modulation, and then transmit the OFDM symbol including the RACH preamble. Here, the terminal may map the RACH preamble to the RACH opportunity (RO) corresponding to the received SSB. Next, although in Fig.13 Not illustrated in the figure, a terminal random access process may be performed.

[0214] Fig.14An example of a process of transmitting a partial or full sequence sample of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.14 A method of operating a terminal is illustrated.

[0215] Reference Fig.14 , in step S1401, the terminal determines whether the transmission bandwidth is less than the required bandwidth. According to an embodiment, the terminal determines whether the transmission bandwidth is less than the required bandwidth by comparing the available bandwidth and the bandwidth required for sending the RACH preamble code including the specified number of samples. Here, if the RACH preamble code to be sent is a long preamble code, the required bandwidth is a bandwidth including 839 or more REs, and if the RACH preamble code to be sent is a short preamble code, the required bandwidth is a bandwidth including 139 or more REs. That is, the terminal can determine whether the transmission bandwidth is less than the required bandwidth by comparing the total number of REs according to the available RBs within the transmission bandwidth and the number of REs required according to the sequence samples of the RACH preamble code. The total number of REs according to the available RBs within the transmission bandwidth may become different according to the SCS. For example, referring to Table 5, when the transmission bandwidth is 5MHz and the SCS is 30kHz, the total number of REs according to the available RBs may be 132 (11x12). Here, if the RACH preamble code to be sent is a short preamble code, since at least 139 REs are required, the terminal can determine that the transmission bandwidth is less than the required bandwidth. As another example, referring to Table 5, when the transmission bandwidth is 5 MHz and the SCS is 15 kHz, the total number of REs according to the available RBs may be 300 (25x12). Here, if the RACH preamble to be transmitted is a short preamble, since at least 139 REs are required, the terminal may determine that the transmission bandwidth is greater than the required bandwidth.

[0216] In the case where the transmission bandwidth is less than the required bandwidth, in step S1403, the terminal determines the sequence samples to be transmitted based on the transmission bandwidth. In the case where the transmission bandwidth is less than the required bandwidth, the terminal may determine that all sequence samples with the specified length cannot be transmitted, and determine some sequence samples to be transmitted or sequence samples with a new format among all sequence samples. According to an embodiment, some sequence samples to be transmitted or sequence samples with a new format may be determined based on RACH related information obtained from system information or further based on predefined rules. For example, the terminal may determine the number of samples to be transmitted, the number of samples to be punctured, the position of samples to be punctured, or sequence samples with a new format among all sequence samples based on at least one of the total number of REs corresponding to the transmission bandwidth, RACH related information, and predefined rules. According to an embodiment, in consideration of interference with adjacent frequency bands, some sequence samples to be transmitted may be determined by further considering the number and / or position of REs to be vacated.

[0217] In the case where the transmission bandwidth is greater than or equal to the required bandwidth, in step S1405, the terminal determines a specified number of sequence samples within the transmission bandwidth. In the case where the transmission bandwidth is greater than or equal to the required bandwidth, the terminal may determine that all sequence samples with a specified length may be transmitted, and determine all sequence samples as sequence samples to be transmitted. For example, if the RACH preamble to be transmitted is a short preamble, the terminal may determine 139 sequence samples as sequence samples to be transmitted, and if the RACH preamble to be transmitted is a long preamble, the terminal may determine 893 sequence samples as sequence samples to be transmitted.

[0218] In step S1407, the terminal maps the determined sequence samples to REs within the transmission bandwidth. For example, the terminal may identify the REs to which the sequence samples within the transmission bandwidth are to be mapped, and map the determined sequence samples to the identified REs. Here, the REs to which the sequence samples are to be mapped may be determined based on at least one of RACH-related information and a predefined rule.

[0219] Fig.15 An example of a process of mapping some sequence samples of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.15 A method of operating a terminal is illustrated.

[0220] Reference Fig.15 In step S1501, the terminal determines at least one RE to be vacated. The terminal may determine the number and / or position of REs to be vacated among all REs within the transmission bandwidth. According to an embodiment, the number and / or position of REs to be vacated may be determined according to a predefined rule, or indicated by a high-layer signaling such as SIB or RRC signaling. For example, as described in Embodiment 1-1, Embodiment 1-2, or Embodiment 1-3 of Embodiment #1, the terminal may determine the number and / or position of REs to which sequence samples are not mapped among REs within the transmission bandwidth.

[0221] In step S1503, the terminal maps the sequence samples to the remaining REs except for the at least one RE to be vacated. Here, the terminal may puncture at least one sample in the sequence samples based on the number and / or position of the REs to be vacated. For example, in order to map the sequence samples to the remaining REs (i.e., available REs) except for the at least one RE to be vacated, the terminal may puncture at least one of the sequence samples.

[0222] Fig.16 An example of a process of aligning sequence samples of a RACH preamble in a transmission bandwidth in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.16 A method of operating a terminal is illustrated.

[0223] Reference Fig.16 In step S1601, the terminal determines the position of the sequence to be mapped. According to an embodiment, the terminal may determine the RE at which the sequence mapping starts among all REs within the transmission bandwidth. According to an embodiment, the RE at which the sequence mapping starts may be determined according to a predefined rule, or may be indicated by a high-level signaling such as SIB or RRC signaling. For example, as described in embodiment 2-1 or embodiment 2-2 of embodiment #2, the terminal may determine the starting position of the sequence mapping so that a specific sample of the sequence may be aligned with a specific RE. According to an embodiment, the starting position of the sequence mapping may be determined by considering the number and / or position of the REs to be vacated.

[0224] In step S1603, the terminal maps the sequence samples based on the position of the sequence to be mapped. The terminal may map the sequence samples based on the RE where the sequence mapping starts. For example, in the case where the first sample of the sequence is mapped to align with a specific RE, the terminal may sequentially map the samples of the sequence starting from the specific RE. As another example, in the case where the center sample of the sequence is mapped to align with the center RE, the terminal may map the center sample of the sequence to the center RE, and then sequentially map the samples on the left and right sides of the center sample of the sequence to the REs on the left and right sides of the center RE, respectively. Here, among the sequence samples, at least one sample to be punctured may be determined based on the position of the RE where the mapping starts and the RE to be vacated. For example, the terminal may map the sequence samples to the RE within the transmission bandwidth based on the determined position of the RE, but may not map the samples to the RE to be vacated, and puncture the sequence samples not mapped to the RE.

[0225] Fig.17 An example of a process of determining a sequence sample length of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.17 A method of operating a terminal is illustrated.

[0226] Reference Fig.17 In step S1701, the terminal determines the length of the sequence. The terminal may determine the length of the sequence as a prime number less than the required sequence length. The required sequence length may be determined based on at least one of the number of REs within the transmission bandwidth and the number of REs to be vacated. For example, as described in Implementation 3-1, Implementation 3-2, Implementation 3-3, or Implementation 3-4 of Implementation #3, the terminal may determine the length of the sequence based on the required sequence length.

[0227] In step S1703, the terminal maps the sequence samples with the determined length to the REs within the transmission bandwidth. Here, the terminal may identify the number and / or position of the REs to be vacated among the REs within the transmission bandwidth, and map the sequence samples with the determined length to the remaining REs. The number and / or position of the REs to be vacated may be determined according to a predefined rule, or indicated by a high-level signaling such as SIB or RRC signaling. The terminal may puncture the samples that are not mapped to the REs among the sequence samples with the determined length.

[0228] Fig.18 An example of a process of repeatedly mapping sequence samples of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.18 A method of operating a terminal is illustrated.

[0229] Reference Fig.18 In step S1801, the terminal determines the number of repetitions. The terminal may determine the number of repetitions of the sequence sample for repeatedly transmitting the RACH preamble. For example, as described in Implementation 4-1 or Implementation 4-2 of Implementation #4, the terminal may determine the number of repetitions. According to an implementation, the number of repetitions may be determined according to a predefined rule or indicated by a higher layer signaling such as SIB or RRC signaling. That is, according to an implementation, the terminal may receive control information including an indication that the number of repetitions defined in the preamble format should be increased.

[0230] In step S1803, the terminal repeatedly maps the sequence samples based on the number of repetitions. For example, in order to repeatedly transmit the sequence samples, the terminal may repeatedly map the sequence samples to available REs over time based on the number of repetitions. Available REs include REs excluding the REs to be vacated.

[0231] Fig.19 An example of a process of determining a starting RB for mapping a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.19 A method of operating a terminal is illustrated.

[0232] Reference Fig.19, in step S1901, the terminal determines the starting RB based on the RB offset. The terminal may identify the RB offset based on a predetermined rule or system information, and determine the starting RB based on the RB offset. For example, as described in implementation #5, based on the RB offset, the terminal may determine the RB to which the sequence sample is to be mapped among multiple RBs within the transmission bandwidth. Here, the terminal may determine the RB to be vacated based on the starting RB. For example, in the case where there are a total of 12 RBs within the transmission bandwidth and 11 of the 12 RBs are used, if the starting RB is the first RB, the terminal may determine the last RB as the RB to be vacated. In addition, if the starting RB is the second RB, the terminal may determine the first RB as the RB to be vacated. According to the implementation, the RB offset may indicate an RB to be retained as unused or an RB to be vacated.

[0233] In step S1903, the terminal determines the starting RE in the starting RB. The terminal may determine the starting RE in the starting RB based on a predetermined rule or system information. For example, as described in implementation #5, the terminal may determine the number and / or position of REs to be vacated based on a predetermined rule or system information, and determine the starting RE based on this.

[0234] In step S1905, the terminal maps the sequence samples based on the starting RE of the starting RB. The terminal may map the sequence samples to the remaining REs excluding the RB to be left blank and the RE to be vacated, and puncture the unmapped samples.

[0235] Fig. 20 An example of a process of mapping sequence samples based on usage restriction of a RACH preamble in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig. 20 A method of operating a terminal is illustrated.

[0236] Reference Fig. 20 In step S2001, the terminal identifies a sequence with restricted use. The terminal may identify information related to a sequence with restricted use based on a predefined rule or high-level signaling. For example, as described in Implementation 6-1, Implementation 6-2, Implementation 6-3, Implementation 6-4, or Implementation 6-5 of Implementation #6, the terminal may identify information about a sequence with restricted use in a specified SCS, a sequence format with restricted use, and a PRACH configuration index and SCS with restricted use. The specified SCS may be determined based on high-level signaling.

[0237] In step S2003, the terminal maps sequence samples by considering the sequence with limited use. Based on the sequence with limited use, the terminal can determine an available sequence, map samples of the determined sequence to available REs within the transmission bandwidth, and puncture unmapped samples. In addition, the available REs can be determined based on the number and / or position of REs to be vacated determined by predefined rules or high-level signaling.

[0238] Fig.21 An example of a process of receiving a RACH preamble for random access in a wireless communication system according to an embodiment of the present disclosure is illustrated. Fig.21 A method for operating a base station is illustrated.

[0239] Reference Fig.21 In step S2101, the base station sends system information to the terminal. For example, the base station may send MIB and at least one SIB. Fig.21 Not illustrated in the figure, but before this step, the base station may send an SSB including at least one synchronization signal to the terminal. The terminal may obtain information for accessing the base station and information for performing subsequent communication processes with the base station. According to an embodiment, the system information may include information related to RACH. For example, the information related to RACH may indicate and / or include at least one of the following items: the number and / or position of REs to be punctured in the PRB used for RACH transmission, an RB offset indicating the RB to be sent in the RACH transmission among the RBs within the transmission bandwidth, the use of restricted sequence formats, whether to use new sequence formats, and rate matching information.

[0240] In step S2103, the base station receives a RACH preamble from the terminal. The base station may receive the RACH preamble sent from the terminal in one of the ROs included in the RACH resources indicated by the system information. Here, according to the RO in which the RACH preamble is detected, the base station may identify the downlink beam selected by the terminal.

[0241] In step S2105, the base station sends a random access response message to the terminal. That is, the base station can generate a random access response message for the terminal and send a DCI including scheduling information for the random access response message and the random access response message. Next, although Fig.21 Not illustrated in the figure, the base station can perform RRC signaling for connection establishment.

[0242] 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 high layer signal).

[0243] 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.

[0244] Industrial Applicability

[0245] 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.

[0246] 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.

[0247] 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 the following steps: Receive system information; Obtaining information related to a random access channel RACH based on the system information; identifying a type of available RACH preamble based on a transmit bandwidth of the terminal; selecting a RACH preamble based on the information related to the RACH and the type; as well as The selected RACH preamble is transmitted via the RACH.

2. The method according to claim 1, further comprising the steps of: Control information is obtained, the control information indicating at least one of a subcarrier spacing SCS, a sequence, and a preamble format that is limited or available according to the transmission bandwidth of the terminal.

3. The method according to claim 2, wherein: The control information indicates whether use of a RACH preamble having at least one SCS is restricted or available.

4. The method according to claim 2, wherein: The control information indicates that usage of a RACH preamble having at least one length is restricted.

5. The method according to claim 2, wherein: The step of transmitting the selected RACH preamble through the RACH includes transmitting the RACH preamble by additionally using resources belonging to a guard band based on a configuration related to preamble transmission with limited SCS and sequence length received through the control information.

6. The method according to claim 2, wherein: The step of transmitting the selected RACH preamble through the RACH includes transmitting the RACH preamble by using a resource block RB reallocated with an SCS smaller than the configured SCS based on a configuration related to preamble transmission with limited SCS and sequence length received through the control information.

7. The method according to claim 1, wherein: The step of transmitting the selected RACH preamble through the RACH includes: based on the number of sequence samples of the selected RACH preamble being greater than the number of resource elements RE within the transmission bandwidth, puncturing at least one of the sequence samples.

8. The method according to claim 7, wherein: The remaining sequence samples determined by puncturing at least one of the sequence samples are mapped to the remaining REs among the RBs within the transmission bandwidth except for the specific resource elements REs in each RB at the two boundaries, or are mapped to the remaining REs among the RBs within the transmission bandwidth except for the specific REs in one RB at the two boundaries.

9. The method according to claim 7, wherein: The remaining sequence samples determined by puncturing at least one of the sequence samples are mapped starting from the first RE within the transmission bandwidth, or are mapped such that a center sample of the remaining sequence samples is aligned with a center RE within the transmission bandwidth.

10. The method according to claim 1, wherein: The step of transmitting the selected RACH preamble through the RACH includes determining a RACH sequence having a length equal to a maximum prime number, the maximum prime number being less than the number of available REs according to the transmission bandwidth of the terminal.

11. The method according to claim 1, further comprising the steps of: Control information is obtained, the control information including an indication to increase a number of repetitions defined by a preamble format.

12. A method for operating a base station in a wireless communication system, the method comprising the steps of: Sending system information including information related to a random access channel RACH; as well as receiving a RACH preamble from a terminal via the RACH, The RACH preamble code belongs to the type of available RACH preamble codes based on the transmission bandwidth of the terminal.

13. 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: Receive system information; Obtaining information related to a random access channel RACH based on the system information; identifying a type of available RACH preamble based on a transmit bandwidth of the terminal; selecting a RACH preamble based on the information related to the RACH and the type; and The selected RACH preamble is transmitted via the RACH.

14. 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 system information including information related to a random access channel RACH; and receiving a RACH preamble from a terminal via the RACH, The RACH preamble code belongs to the type of available RACH preamble codes based on the transmission bandwidth of the terminal.

15. 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: Receive system information; Obtaining information related to a random access channel RACH based on the system information; identifying a type of available RACH preamble based on a transmission bandwidth of the communication device; selecting a RACH preamble based on the information related to the RACH and the type; and The selected RACH preamble is transmitted via the RACH.

16. 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: Receive system information; Obtaining information related to a random access channel RACH based on the system information; identifying a type of available RACH preamble based on a transmission bandwidth of the device; selecting a RACH preamble based on the information related to the RACH and the type; as well as The selected RACH preamble is transmitted via the RACH.

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