Method and device for beam refinement in wireless communication system

Abstract

A method performed by a terminal in a wireless communication system according to an embodiment of the present disclosure may comprise the steps of: receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information pertaining to a pilot signal; receiving a plurality of pilot signals, downlink control information (DCI), and system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received on the basis of the information pertaining to the pilot signal included in the MIB; selecting an optimal pilot signal from among the plurality of pilot signals; and transmitting, to the base station, a random access channel (RACH) in a random access channel occasion (RO, RACH occasion) related to the optimal pilot signal.

Description

Beam refinement method and device in a wireless communication system

[0001] The present disclosure relates to a method and device for beam refinement in a wireless communication system. Specifically, the present disclosure relates to a method and device for beam refinement for improving downlink signal quality during an initial cell search procedure in a wireless communication system.

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

[0003] In particular, as numerous communication devices demand greater communication capacity, enhanced mobile broadband (eMBB) communication technologies are being proposed, improving upon existing radio access technology (RAT). Furthermore, massive machine type communications (mMTC), which connects numerous devices and objects to provide diverse services anytime and anywhere, as well as communication systems that consider reliability and latency-sensitive services / user equipment (UE), are being proposed. Various technological configurations are being proposed for these purposes.

[0004] In order to solve the above-described problem, the technical task of the present disclosure is to provide a beam refinement method and device that can perform a BS Tx beam refinement operation during an initial cell search operation instead of a beam refinement operation performed after a conventional initial cell search operation by utilizing an FDB after receiving an SSB or after receiving a DCI / SIB1.

[0005] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0006] According to various embodiments of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system may include the steps of: receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information about a pilot signal; receiving a plurality of pilot signals, downlink control information (DCI) and a system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received based on the information about the pilot signal included in the MIB; selecting an optimal pilot signal among the plurality of pilot signals; and transmitting a random access channel (RACH) in a random access channel occasion (RACH) associated with the optimal pilot signal to the base station.

[0007] According to various embodiments of the present disclosure, the information about the pilot signal may include information about the start symbol position and symbol length of the plurality of pilot signals or frequency allocation information of the plurality of pilot signals.

[0008] According to various embodiments of the present disclosure, the frequency allocation information of the plurality of pilot signals may be determined based on the number of the plurality of pilot signals, the number of the plurality of pilot signals, information about a beam angle steered by the base station, and information about an angular interval at which the plurality of pilot signals are transmitted.

[0009] According to various embodiments of the present disclosure, the step of receiving the plurality of pilot signals, the DCI and the SIB 1 from the base station may include the step of receiving the DCI and the SIB 1 after receiving the plurality of pilot signals from the base station or the step of receiving the plurality of pilot signals after receiving the DCI and the SIB 1 from the base station.

[0010] According to various embodiments of the present disclosure, the step of selecting the optimal pilot signal among the plurality of pilot signals may further include the step of obtaining information about pilot signal frequency resources of each of the plurality of pilot signals, and the step of obtaining information about a resource block to which each of the plurality of pilot signals is mapped based on the information about the pilot signal frequency resources of each of the plurality of pilot signals and a center frequency.

[0011] According to various embodiments of the present disclosure, the step of selecting the optimal pilot signal among the plurality of pilot signals may include the step of measuring the RSRP (reference signal received power) of each of the plurality of pilot signals and the step of selecting the pilot signal having the largest RSRP measurement value among the plurality of pilot signals as the optimal pilot signal.

[0012] According to various embodiments of the present disclosure, the method further includes the steps of receiving MSG (message) 2 from the base station, transmitting MSG 3 to the base station, and receiving MSG 4 from the base station, wherein the MSG 2, the MSG 3, and the MSG 4 can be mapped to the resource to which the optimal pilot signal is mapped or a resource adjacent to the resource to which the optimal pilot signal is mapped.

[0013] According to various embodiments of the present disclosure, a user equipment (UE) operating in a communication system may include one or more transceivers, one or more processors controlling the one or more transceivers, and a memory including one or more instructions to be executed by the one or more processors, wherein the one or more instructions may include: receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information regarding a pilot signal; receiving a plurality of pilot signals, downlink control information (DCI), and a system information block (SIB) 1 from the BS, wherein the plurality of pilot signals are received based on the information regarding the pilot signal included in the MIB; selecting an optimal pilot signal among the plurality of pilot signals; and transmitting a random access channel (RACH) in a random access channel occasion (RACH) associated with the optimal pilot signal to the BS.

[0014] According to various embodiments of the present disclosure, a method of operating a base station (BS) in a wireless communication system may include the steps of: transmitting a synchronization signal block (SSB) including a master information block (MIB) to a user equipment (UE) base station (BS), wherein the MIB includes information about a pilot signal; transmitting a plurality of pilot signals, downlink control information (DCI) and a system information block (SIB) 1 to the UE, wherein the plurality of pilot signals are transmitted based on the information about the pilot signal included in the MIB; and receiving a random access channel (RACH) from the UE in a random access channel occasion (RACH) associated with an optimal pilot signal among the plurality of pilot signals.

[0015] According to various embodiments of the present disclosure, the information about the pilot signal may include information about the start symbol position and symbol length of the plurality of pilot signals or frequency allocation information of the plurality of pilot signals.

[0016] According to various embodiments of the present disclosure, the frequency allocation information of the plurality of pilot signals may be determined based on the number of the plurality of pilot signals, the number of the plurality of pilot signals, information about a beam angle steered by the base station, and information about an angular interval at which the plurality of pilot signals are transmitted.

[0017] According to various embodiments of the present disclosure, the step of transmitting the plurality of pilot signals, the DCI, and the SIB 1 to the terminal may include the step of transmitting the DCI and the SIB 1 after transmitting the plurality of pilot signals to the terminal, or the step of transmitting the plurality of pilot signals after transmitting the DCI and the SIB 1 to the terminal.

[0018] According to various embodiments of the present disclosure, the method further includes the steps of transmitting MSG (message) 2 to the terminal, receiving MSG 3 from the terminal, and transmitting MSG 4 to the terminal, wherein the MSG 2, the MSG 3, and the MSG 4 can be mapped to the resource to which the optimal pilot signal is mapped or a resource adjacent to the resource to which the optimal pilot signal is mapped.

[0019] According to various embodiments of the present disclosure, a base station (BS) operating in a communication system may include one or more transceivers, one or more processors controlling the one or more transceivers, and a memory including one or more instructions to be executed by the one or more processors, wherein the one or more instructions may include: transmitting a synchronization signal block (SSB) including a master information block (MIB) to a user equipment (UE) base station (BS), the MIB including information about a pilot signal; transmitting a plurality of pilot signals, downlink control information (DCI) and a system information block (SIB) 1 to the UE, the plurality of pilot signals being transmitted based on the information about the pilot signal included in the MIB; and receiving a random access channel (RACH) in a random access channel occasion (RACH) associated with an optimal pilot signal among the plurality of pilot signals from the UE.

[0020] According to various embodiments of the present disclosure, a device including one or more memories and one or more processors functionally connected to the one or more memories, wherein the one or more processors can cause the device to perform the steps of: receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), the MIB including information about a pilot signal; receiving a plurality of pilot signals, downlink control information (DCI) and a system information block (SIB) 1 from the base station, the plurality of pilot signals being received based on the information about the pilot signal included in the MIB; selecting an optimal pilot signal among the plurality of pilot signals; and transmitting, to the base station, a random access channel (RACH) in a random access channel occasion (RACH) associated with the optimal pilot signal.

[0021] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media storing one or more commands may be operable to perform the steps of: receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), the MIB including information about a pilot signal; receiving a plurality of pilot signals, downlink control information (DCI) and a system information block (SIB) 1 from the BS, the plurality of pilot signals being received based on the information about the pilot signal included in the MIB; selecting an optimal pilot signal among the plurality of pilot signals; and transmitting, to the BS, a random access channel (RACH) in a random access channel occasion (RACH) associated with the optimal pilot signal.

[0022] According to the present disclosure, a BS Tx beam refinement operation can be performed quickly.

[0023] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0024] The accompanying drawings are intended to aid in understanding the present disclosure and, together with detailed descriptions, may provide embodiments of the present disclosure. 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. Reference numerals in each drawing may indicate structural elements.

[0025] Figure 1 is a drawing showing an example of a communication system applicable to this specification.

[0026] Figure 2 is a drawing showing an example of a wireless device applicable to this specification.

[0027] FIG. 3 is a diagram illustrating a method for processing a transmission signal applicable to the present specification.

[0028] FIG. 4 is a drawing showing another example of a wireless device applicable to this specification.

[0029] FIG. 5 is a drawing showing an example of a mobile device applicable to this specification.

[0030] Figure 6 is a diagram showing physical channels applicable to this specification and a signal transmission method using them.

[0031] Figure 7 is a diagram showing the structure of a wireless frame applicable to this specification.

[0032] Figure 8 is a drawing showing a slot structure applicable to this specification.

[0033] FIG. 9 is a diagram showing an example of a communication structure that can be provided in a 6G system applicable to this specification.

[0034] Figure 10 shows an example of a perceptron structure.

[0035] Figure 11 shows an example of a multilayer perceptron structure.

[0036] Figure 12 shows an example of a deep neural network.

[0037] Figure 13 shows an example of a convolutional neural network.

[0038] Figure 14 is a diagram showing an example of a filter operation in a convolutional neural network.

[0039] Figure 15 shows an example of a neural network structure in which a recurrent loop exists.

[0040] Figure 16 shows an example of the operating structure of a recurrent neural network.

[0041] Figure 17 is a diagram showing an electromagnetic spectrum applicable to this specification.

[0042] Fig. 18 is a drawing showing a THz communication method applicable to this specification.

[0043] FIG. 19 is a diagram illustrating a THz wireless communication transceiver applicable to the present specification.

[0044] Fig. 20 is a drawing showing a THz signal generation method applicable to the present specification.

[0045] Figure 21 is a drawing showing a wireless communication transceiver applicable to this specification.

[0046] Figure 22 is a drawing showing a transmitter structure applicable to this specification.

[0047] Fig. 23 is a drawing showing a modulator structure applicable to this specification.

[0048] FIG. 24 is a diagram illustrating an example of a method for determining a beam width in a wireless communication system.

[0049] Figure 25 is a diagram illustrating an example of a case where beam alignment is not correct in a wireless communication system.

[0050] Fig. 26 is a drawing illustrating an example in which a beam angle is adjusted according to the position of a frequency in a wireless communication system.

[0051] Fig. 27 is a diagram illustrating an example of beam gain due to beam misalignment according to the number of antennas in a wireless communication system.

[0052] FIG. 28 is a drawing illustrating an example of an overall procedure according to one embodiment of the present disclosure.

[0053] FIG. 29 is a diagram illustrating an example of an SSB signal broadcasting method according to one embodiment of the present disclosure.

[0054] FIG. 30 is a diagram illustrating an example of pilot signal mapping according to one embodiment of the present disclosure.

[0055] FIGS. 31 to 32 are diagrams illustrating examples of mapping of a pilot signal in the time domain according to one embodiment of the present disclosure.

[0056] FIG. 33 is a diagram illustrating an example of pilot signal mapping according to one embodiment of the present disclosure.

[0057] FIG. 34 is a diagram illustrating an example of mapping of a pilot signal in the frequency domain according to one embodiment of the present disclosure.

[0058] FIG. 35 is a diagram illustrating an example of frequency allocation information according to one embodiment of the present disclosure.

[0059] FIGS. 36 to 38 are diagrams illustrating an example of a RACH transmission method according to one embodiment of the present disclosure.

[0060] FIG. 39 is a diagram illustrating an example of a resource allocation method according to one embodiment of the present disclosure.

[0061] Figure 40 is a flowchart of a signal transmission and reception method according to one embodiment of the present disclosure.

[0062] FIG. 41 is a flowchart of a signal transmission and reception method according to another embodiment of the present disclosure.

[0063] The following embodiments combine the components and features of this specification in a predetermined form. Each component or feature may be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, some components and / or features may be combined to form embodiments of this specification. The order of operations described in the embodiments of this specification may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

[0064] In the description of the drawings, procedures or steps that may obscure the gist of the present specification are not described, and procedures or steps that can be understood by a person skilled in the art are also not described.

[0065] Throughout the specification, when a part is said to "comprising" (or including) a certain component, this does not mean that other components are excluded, but rather that other components can be included, unless specifically stated otherwise. In addition, terms such as "...part," "...unit," and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. In addition, the words "a" or "an," "one," "the," and similar related words may be used in the context of describing this specification (especially in the context of the claims below) to include both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0066] The embodiments of this specification have been described with a focus on the data transmission and reception relationship between a base station and a mobile station. Here, the base station is understood as a terminal node of a network that directly communicates with the mobile station. Certain operations described herein as being performed by the base station may, in some cases, be performed by an upper node of the base station.

[0067] That is, in a network consisting of multiple network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this case, the term 'base station' may be replaced by terms such as fixed station, Node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.

[0068] Additionally, in the embodiments of the present specification, the term terminal may be replaced with terms such as user equipment (UE), mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, or advanced mobile station (AMS).

[0069] Additionally, a transmitter refers to a fixed and / or mobile node that provides data or voice services, and a receiver refers to a fixed and / or mobile node that receives data or voice services. Therefore, for uplink, a mobile station can be the transmitter, and a base station can be the receiver. Similarly, for downlink, a mobile station can be the receiver, and a base station can be the transmitter.

[0070] Embodiments of the present specification may be supported by standard documents disclosed in at least one of wireless access systems, such as IEEE 802.xx system, 3rd Generation Partnership Project (3GPP) system, 3GPP Long Term Evolution (LTE) system, 3GPP 5G (5th generation) NR (New Radio) system and 3GPP2 system, and in particular, embodiments of the present specification may be supported by 3GPP TS (technical specification) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPP TS 38.331 documents.

[0071] Furthermore, the embodiments of this specification may be applied to other wireless access systems and are not limited to the aforementioned systems. For example, they may also be applicable to systems implemented after the 3GPP 5G NR system, and are not limited to a specific system.

[0072] That is, obvious steps or parts not described in the embodiments of this specification may be explained by reference to the above documents. In addition, all terms disclosed in this specification may be explained by the above standard documents.

[0073] Hereinafter, preferred embodiments according to the present specification will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the present specification and is not intended to represent the only embodiments in which the technical components of the present specification may be implemented.

[0074] Additionally, specific terms used in the embodiments of this specification are provided to aid in understanding of this specification, and the use of these specific terms may be changed to other forms without departing from the technical spirit of this specification.

[0075] The following technology can be applied to various wireless access systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access).

[0076] In order to make the following description clear, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical idea of ​​the present invention is not limited thereto. LTE may refer to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 may be referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 may be referred to as LTE-A pro. 3GPP NR may refer to technology after TS 38.xxx Release 15. 3GPP 6G may refer to technology after TS Release 17 and / or Release 18. "xxx" refers to a standard document detail number. LTE / NR / 6G may be collectively referred to as a 3GPP system.

[0077] For background information, terms, abbreviations, etc. used in this specification, reference may be made to standard documents published prior to the invention of the present invention. For example, reference may be made to the 36.xxx and 38.xxx standard documents.

[0078] Communication systems applicable to this specification

[0079] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0080] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0081] FIG. 1 is a diagram illustrating an example of a communication system applicable to the present specification. Referring to FIG. 1, a communication system (100) applicable to the present specification includes a wireless device, a base station, and a network. Here, a wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (extended reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI (artificial intelligence) device / server (100g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicles (100b-1, 100b-2) may include unmanned aerial vehicles (UAVs) (e.g., drones). The XR devices (100c) include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. The portable devices (100d) may include smartphones, smart pads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.), etc. The home appliances (100e) may include TVs, refrigerators, washing machines, etc. The IoT devices (100f) may include sensors, smart meters, etc.For example, the base station (120) and the network (130) may also be implemented as wireless devices, and a specific wireless device (120a) may act as a base station / network node to other wireless devices.

[0082] Wireless devices (100a to 100f) can be connected to a network (130) via a base station (120). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (100g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (120) / network (130), but can also communicate directly (e.g., sidelink communication) without going through the base station (120) / network (130). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). In addition, IoT devices (100f) (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0083] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base stations (120), and base stations (120) / base stations (120). Here, the wireless communication / connection can be established through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and base station-to-base station communication (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and base station / wireless device, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of the various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes may be performed based on various proposals of this specification.

[0084] Communication systems applicable to this specification

[0085] FIG. 2 is a diagram illustrating an example of a wireless device applicable to this specification.

[0086] Referring to FIG. 2, the first wireless device (200a) and the second wireless device (200b) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (200a), the second wireless device (200b)} can correspond to {the wireless device (100x), the base station (120)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 1.

[0087] A first wireless device (200a) includes one or more processors (202a) and one or more memories (204a), and may further include one or more transceivers (206a) and / or one or more antennas (208a). The processor (202a) controls the memories (204a) and / or the transceivers (206a), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (202a) may process information in the memory (204a) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (206a). In addition, the processor (202a) may receive a wireless signal including second information / signals via the transceivers (206a), and then store information obtained from signal processing of the second information / signals in the memory (204a). The memory (204a) may be connected to the processor (202a) and may store various information related to the operation of the processor (202a). For example, the memory (204a) may perform some or all of the processes controlled by the processor (202a), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. Here, the processor (202a) and the memory (204a) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206a) may be connected to the processor (202a) and may transmit and / or receive wireless signals via one or more antennas (208a). The transceiver (206a) may include a transmitter and / or a receiver. The transceiver (206a) may be used interchangeably with an RF (radio frequency) unit. In this specification, wireless device may also mean a communication modem / circuit / chip.

[0088] The second wireless device (200b) includes one or more processors (202b), one or more memories (204b), and may further include one or more transceivers (206b) and / or one or more antennas (208b). The processor (202b) controls the memories (204b) and / or the transceivers (206b), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (202b) may process information in the memory (204b) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206b). In addition, the processor (202b) may receive a wireless signal including fourth information / signals via the transceivers (206b), and then store information obtained from signal processing of the fourth information / signals in the memory (204b). The memory (204b) may be connected to the processor (202b) and may store various information related to the operation of the processor (202b). For example, the memory (204b) may perform some or all of the processes controlled by the processor (202b), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. Here, the processor (202b) and the memory (204b) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206b) may be connected to the processor (202b) and may transmit and / or receive wireless signals via one or more antennas (208b). The transceiver (206b) may include a transmitter and / or a receiver. The transceiver (206b) may be used interchangeably with an RF unit. In this specification, wireless device may also mean a communication modem / circuit / chip.

[0089] Hereinafter, hardware elements of the wireless device (200a, 200b) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (202a, 202b). For example, one or more processors (202a, 202b) may implement one or more layers (e.g., functional layers such as physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and service data adaptation protocol (SDAP)). One or more processors (202a, 202b) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. One or more processors (202a, 202b) may generate messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. One or more processors (202a, 202b) may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed herein and provide the signals to one or more transceivers (206a, 206b). One or more processors (202a, 202b) may receive signals (e.g., baseband signals) from one or more transceivers (206a, 206b) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0090] One or more processors (202a, 202b) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (202a, 202b) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors (202a, 202b). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this specification may be implemented using firmware or software configured to perform one or more processors (202a, 202b) or stored in one or more memories (204a, 204b) and executed by one or more processors (202a, 202b). The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this specification may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0091] One or more memories (204a, 204b) may be coupled to one or more processors (202a, 202b) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (204a, 204b) may be configured as read only memory (ROM), random access memory (RAM), erasable programmable read only memory (EPROM), flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories (204a, 204b) may be located internally and / or externally to the one or more processors (202a, 202b). Additionally, the one or more memories (204a, 204b) may be coupled to the one or more processors (202a, 202b) via various technologies, such as wired or wireless connections.

[0092] One or more transceivers (206a, 206b) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this specification, to one or more other devices. One or more transceivers (206a, 206b) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this specification, from one or more other devices. For example, one or more transceivers (206a, 206b) can be coupled to one or more processors (202a, 202b) and can transmit and receive wireless signals. For example, one or more processors (202a, 202b) can control one or more transceivers (206a, 206b) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (202a, 202b) may control one or more transceivers (206a, 206b) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (206a, 206b) may be coupled to one or more antennas (208a, 208b), and one or more transceivers (206a, 206b) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via one or more antennas (208a, 208b). In the present specification, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (206a, 206b) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (202a, 202b).One or more transceivers (206a, 206b) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (202a, 202b) from baseband signals to RF band signals. For this purpose, one or more transceivers (206a, 206b) may include an (analog) oscillator and / or filter.

[0093] FIG. 3 is a diagram illustrating a method for processing a transmission signal applied to the present specification. For example, the transmission signal may be processed by a signal processing circuit. At this time, the signal processing circuit (300) may include a scrambler (310), a modulator (320), a layer mapper (330), a precoder (340), a resource mapper (350), and a signal generator (360). At this time, as an example, the operations / functions of FIG. 3 may be performed in the processors (202a, 202b) and / or the transceivers (206a, 206b) of FIG. 2. Furthermore, as an example, the hardware elements of FIG. 3 may be implemented in the processors (202a, 202b) and / or the transceivers (206a, 206b) of FIG. 2. For example, blocks 310 to 350 may be implemented in the processor (202a, 202b) of FIG. 2, and block 360 may be implemented in the transceiver (206a, 206b) of FIG. 2, and are not limited to the above-described embodiments.

[0094] The codeword can be converted into a wireless signal through the signal processing circuit (300) of FIG. 3. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transport block (e.g., a UL-SCH transport block, a DL-SCH transport block). The wireless signal may be transmitted through various physical channels (e.g., a PUSCH, a PDSCH) of FIG. 6. Specifically, the codeword can be converted into a bit sequence scrambled by a scrambler (310). The scramble sequence used for scrambling is generated based on an initialization value, and the initialization value may include ID information of the wireless device, etc. The scrambled bit sequence can be modulated into a modulation symbol sequence by a modulator (320). The modulation scheme may include pi / 2-binary phase shift keying (pi / 2-BPSK), m-phase shift keying (m-PSK), m-quadrature amplitude modulation (m-QAM), etc.

[0095] A complex modulation symbol sequence can be mapped to one or more transmission layers by a layer mapper (330). The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (340) (precoding). The output z of the precoder (340) can be obtained by multiplying the output y of the layer mapper (330) by an N*M precoding matrix W. Here, N is the number of antenna ports, and M is the number of transmission layers. Here, the precoder (340) can perform precoding after performing transform precoding (e.g., discrete Fourier transform (DFT) transform) on the complex modulation symbols. In addition, the precoder (340) can perform precoding without performing transform precoding.

[0096] The resource mapper (350) can map modulation symbols of each antenna port to time-frequency resources. The time-frequency resources can include multiple symbols (e.g., CP-OFDMA symbols, DFT-s-OFDMA symbols) in the time domain and multiple subcarriers in the frequency domain. The signal generator (360) generates a wireless signal from the mapped modulation symbols, and the generated wireless signal can be transmitted to another device through each antenna. To this end, the signal generator (360) can include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), a frequency uplink converter, and the like.

[0097] The signal processing process for receiving signals in a wireless device can be configured in reverse order of the signal processing process (310-360) of FIG. 3. For example, a wireless device (e.g., 200a, 200b of FIG. 2) can receive wireless signals from the outside through an antenna port / transceiver. The received wireless signals can be converted into baseband signals through a signal restorer. For this purpose, the signal restorer can include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Thereafter, the baseband signal can be restored to a codeword through a resource demapper process, a postcoding process, a demodulation process, and a descrambling process. The codewords can be restored to the original information blocks through decoding. Accordingly, a signal processing circuit (not shown) for a received signal may include a signal restorer, a resource de-mapper, a postcoder, a demodulator, a de-scrambler, and a decoder.

[0098] Wireless device structure applicable to this specification

[0099] FIG. 4 is a diagram illustrating another example of a wireless device to which the present specification applies.

[0100] Referring to FIG. 4, the wireless device (400) corresponds to the wireless devices (200a, 200b) of FIG. 2 and may be composed of various elements, components, units, and / or modules. For example, the wireless device (400) may include a communication unit (410), a control unit (420), a memory unit (430), and additional elements (440). The communication unit may include a communication circuit (412) and a transceiver(s) (414). For example, the communication circuit (412) may include one or more processors (202a, 202b) and / or one or more memories (204a, 204b) of FIG. 2. For example, the transceiver(s) (414) may include one or more transceivers (206a, 206b) and / or one or more antennas (208a, 208b) of FIG. 2. The control unit (420) is electrically connected to the communication unit (410), the memory unit (430), and the additional elements (440) and controls the overall operation of the wireless device. For example, the control unit (420) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (430). In addition, the control unit (420) may transmit information stored in the memory unit (430) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (410), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (430).

[0101] The additional element (440) may be configured in various ways depending on the type of the wireless device. For example, the additional element (440) may include at least one of a power unit / battery, an input / output unit, a driving unit, and a computing unit. Although not limited thereto, the wireless device (400) may be implemented in the form of a robot (Fig. 1, 100a), a vehicle (Fig. 1, 100b-1, 100b-2), an XR device (Fig. 1, 100c), a portable device (Fig. 1, 100d), a home appliance (Fig. 1, 100e), an IoT device (Fig. 1, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 1, 140), a base station (Fig. 1, 120), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0102] In FIG. 4, various elements, components, units / parts, and / or modules within the wireless device (400) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (410). For example, within the wireless device (400), the control unit (420) and the communication unit (410) may be wired, and the control unit (420) and a first unit (e.g., 430, 440) may be wirelessly connected via the communication unit (410). In addition, each element, component, unit / part, and / or module within the wireless device (400) may further include one or more elements. For example, the control unit (420) may be composed of a set of one or more processors. For example, the control unit (420) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (430) may be composed of RAM, DRAM (dynamic RAM), ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0103] Mobile devices to which this specification applies

[0104] FIG. 5 is a drawing illustrating an example of a mobile device to which the present specification applies.

[0105] Figure 5 illustrates an example of a mobile device applicable to the present specification. The mobile device may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), or a portable computer (e.g., a laptop, etc.). The mobile device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

[0106] Referring to FIG. 5, the portable device (500) may include an antenna unit (508), a communication unit (510), a control unit (520), a memory unit (530), a power supply unit (540a), an interface unit (540b), and an input / output unit (540c). The antenna unit (508) may be configured as a part of the communication unit (510). Blocks 510 to 530 / 540a to 540c correspond to blocks 410 to 430 / 440 of FIG. 4, respectively.

[0107] The communication unit (510) can transmit and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The control unit (520) can control components of the portable device (500) to perform various operations. The control unit (520) can include an AP (application processor). The memory unit (530) can store data / parameters / programs / codes / commands required for operating the portable device (500). In addition, the memory unit (530) can store input / output data / information, etc. The power supply unit (540a) supplies power to the portable device (500) and can include a wired / wireless charging circuit, a battery, etc. The interface unit (540b) can support connection between the portable device (500) and other external devices. The interface unit (540b) can include various ports (e.g., audio input / output ports, video input / output ports) for connection with external devices. The input / output unit (540c) can input or output video information / signals, audio information / signals, data, and / or information input from a user. The input / output unit (540c) may include a camera, a microphone, a user input unit, a display unit (540d), a speaker, and / or a haptic module.

[0108] For example, in the case of data communication, the input / output unit (540c) obtains information / signals (e.g., touch, text, voice, image, video) input by the user, and the obtained information / signals can be stored in the memory unit (530). The communication unit (510) can convert the information / signals stored in the memory into wireless signals, and transmit the converted wireless signals directly to other wireless devices or to a base station. In addition, the communication unit (510) can receive wireless signals from other wireless devices or base stations, and then restore the received wireless signals to the original information / signals. The restored information / signals can be stored in the memory unit (530) and then output in various forms (e.g., text, voice, image, video, haptic) through the input / output unit (540c).

[0109] Physical channels and general signal transmission

[0110] In a wireless access system, a terminal can receive information from a base station via the downlink (DL) and transmit it to the base station via the uplink (UL). The information transmitted and received between the base station and the terminal includes general data and various control information, and various physical channels exist depending on the type and purpose of the information being transmitted and received.

[0111] FIG. 6 is a diagram illustrating physical channels applicable to this specification and a signal transmission method using them.

[0112] When a terminal is powered on again from a powered-off state or newly enters a cell, it performs an initial cell search operation, such as synchronizing with the base station, in step S611. To this end, the terminal receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station to synchronize with the base station and obtain information such as the cell ID.

[0113] After that, the terminal can obtain broadcast information within the cell by receiving a physical broadcast channel (PBCH) signal from the base station. Meanwhile, the terminal can check the downlink channel status by receiving a downlink reference signal (DL RS) in the initial cell search phase. After completing the initial cell search, the terminal can obtain more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on the physical downlink control channel information in step S612.

[0114] Thereafter, the terminal may perform a random access procedure such as steps S613 to S616 to complete connection to the base station. To this end, the terminal may transmit a preamble through a physical random access channel (PRACH) (S613) and receive a random access response (RAR) for the preamble through a physical downlink control channel and a physical downlink shared channel corresponding thereto (S614). The terminal may transmit a physical uplink shared channel (PUSCH) using scheduling information in the RAR (S615) and perform a contention resolution procedure such as receiving a physical downlink control channel signal and a physical downlink shared channel signal corresponding thereto (S616).

[0115] A terminal that has performed the procedure described above can then perform reception of a physical downlink control channel signal and / or a physical downlink shared channel signal (S617) and transmission of a physical uplink shared channel (PUSCH) signal and / or a physical uplink control channel (PUCCH) signal (S618) as a general uplink / downlink signal transmission procedure.

[0116] Control information transmitted from a terminal to a base station is collectively referred to as uplink control information (UCI). UCI includes hybrid automatic repeat and request acknowledgment / negative ACK (HARQ-ACK / NACK), scheduling request (SR), channel quality indication (CQI), precoding matrix indication (PMI), rank indication (RI), and beam indication (BI) information. UCI is generally transmitted periodically through PUCCH, but depending on the embodiment (e.g., when control information and traffic data must be transmitted simultaneously), it may be transmitted through PUSCH. In addition, the terminal may transmit UCI aperiodically through PUSCH upon request / instruction from the network.

[0117] Figure 7 is a diagram illustrating the structure of a wireless frame applicable to this specification.

[0118] Uplink and downlink transmissions based on the NR system can be based on frames such as those in FIG. 7. At this time, one radio frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). One half-frame can be defined as five 1 ms subframes (SF). One subframe is divided into one or more slots, and the number of slots within a subframe can depend on the subcarrier spacing (SCS). At this time, each slot can contain 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP). When a normal CP is used, each slot can contain 14 symbols. When an extended CP is used, each slot can contain 12 symbols. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol), an SC-FDMA symbol (or DFT-s-OFDM symbol).

[0119] Table 1 shows the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to SCS when a general CP is used, and Table 2 shows the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to SCS when an extended CSP is used.

[0120] [Table 1]

[0121]

[0122] [Table 2]

[0123]

[0124] In Table 1 and Table 2 above, N slot symb represents the number of symbols in the slot, and N frame,μ slot represents the number of slots in the frame, and N subframe,μ slotcan indicate the number of slots within a subframe.

[0125] Additionally, in a system to which the present specification is applicable, OFDM(A) numerologies (e.g., SCS, CP length, etc.) may be set differently between multiple cells merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (conveniently referred to as TU (time unit)) consisting of the same number of symbols may be set differently between the merged cells.

[0126] NR can support multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, a 15 kHz SCS supports wide areas in traditional cellular bands; a 30 kHz / 60 kHz SCS supports dense urban areas, lower latency, and wider carrier bandwidth; and a 60 kHz or higher SCS can support bandwidths greater than 24.25 GHz to overcome phase noise.

[0127] The NR frequency band is defined by two types of frequency ranges (FR1 and FR2). FR1 and FR2 can be configured as shown in the table below. FR2 can also refer to millimeter wave (mmW).

[0128] [Table 3]

[0129]

[0130] In addition, as an example, the numerology described above may be set differently in a communication system to which the present specification is applicable. For example, a terahertz wave (THz) band may be used as a frequency band higher than the FR2 described above. In the THz band, the SCS may be set to be larger than in the NR system, and the number of slots may also be set differently, and is not limited to the above-described embodiment. The THz band will be described later.

[0131] Figure 8 is a drawing illustrating a slot structure applicable to this specification.

[0132] A single slot contains multiple symbols in the time domain. For example, a slot contains seven symbols in a regular CP, but a slot may contain six symbols in an extended CP. A carrier contains multiple subcarriers in the frequency domain. A Resource Block (RB) can be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain.

[0133] Additionally, a Bandwidth Part (BWP) is defined as multiple consecutive (P)RBs in the frequency domain, and can correspond to one numerology (e.g., SCS, CP length, etc.).

[0134] A carrier can contain up to N (e.g., 5) BWPs. Data communication is performed through an activated BWP, and only one BWP can be activated per terminal. Each element in the resource grid is referred to as a Resource Element (RE), to which a single complex symbol can be mapped.

[0135] 6G communication system

[0136] The 6G (wireless communication) system aims to achieve (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) low energy consumption for battery-free IoT devices, (vi) ultra-reliable connectivity, and (vii) connected intelligence with machine learning capabilities. The vision of the 6G system can be divided into four aspects: "intelligent connectivity," "deep connectivity," "holographic connectivity," and "ubiquitous connectivity," and the 6G system can satisfy the requirements as shown in Table 4 below. In other words, Table 4 is a table showing the requirements of the 6G system.

[0137] [Table 4]

[0138]

[0139] At this time, the 6G system may have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine type communications (mMTC), AI integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0140] FIG. 9 is a diagram illustrating an example of a communication structure that can be provided in a 6G system applicable to this specification.

[0141] Referring to Figure 9, 6G systems are expected to have 50 times higher simultaneous wireless communication connectivity than 5G wireless communication systems. URLLC, a key feature of 5G, is expected to become a more prominent technology in 6G communications by providing end-to-end latency of less than 1 ms. Furthermore, 6G systems will have significantly better volumetric spectral efficiency, unlike the commonly used area spectral efficiency. 6G systems can offer extremely long battery life and advanced battery technologies for energy harvesting, eliminating the need for separate charging for mobile devices in 6G systems. Furthermore, new network characteristics in 6G may include:

[0142] - Satellite integrated network: 6G is expected to integrate with satellites to provide a global mobile network. The integration of terrestrial, satellite, and airborne networks into a single wireless communications system could be crucial for 6G.

[0143] Connected Intelligence: Unlike previous generations of wireless communication systems, 6G is revolutionary, upgrading the wireless evolution from "connected objects" to "connected intelligence." AI can be applied at every stage of the communication process (or at every signal processing step, as described below).

[0144] - Seamless integration of wireless information and energy transfer: 6G wireless networks will transfer power to charge the batteries of devices such as smartphones and sensors. Therefore, wireless information and energy transfer (WIET) will be integrated.

[0145] - Ubiquitous super 3-dimension connectivity: Access to networks and core network functions from drones and very low Earth orbit satellites will create super 3-dimension connectivity in 6G ubiquitous.

[0146] Some general requirements for the new network characteristics of 6G, such as the above, may be as follows:

[0147] - Small cell networks: The concept of small cell networks was introduced to improve received signal quality in cellular systems by increasing throughput, energy efficiency, and spectral efficiency. Consequently, small cell networks are essential for 5G and beyond-5G (5GB) communication systems. Accordingly, 6G communication systems also adopt the characteristics of small cell networks.

[0148] Ultra-dense heterogeneous networks: Ultra-dense heterogeneous networks will be another key feature of 6G communication systems. Multi-tier networks comprised of heterogeneous networks improve overall QoS and reduce costs.

[0149] High-capacity backhaul: Backhaul connections are characterized by high-capacity backhaul networks to support high-volume traffic. High-speed fiber optics and free-space optics (FSO) systems may be potential solutions to this problem.

[0150] - Radar technology integrated with mobile technology: High-precision localization (or location-based services) through communications is a key feature of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0151] - Softwarization and virtualization: Softwarization and virtualization are two critical features that form the foundation of the design process for 5GB networks to ensure flexibility, reconfigurability, and programmability. Furthermore, billions of devices can be shared on a shared physical infrastructure.

[0152] Core implementation technology of 6G systems

[0153] - Artificial Intelligence (AI)

[0154] The most crucial and newly introduced technology for 6G systems is AI. 4G systems did not involve AI. 5G systems will support partial or very limited AI. However, 6G systems will fully support AI for automation. Advances in machine learning will create more intelligent networks for real-time communications in 6G. Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analyses to determine how complex target tasks should be performed. In other words, AI can increase efficiency and reduce processing delays.

[0155] Time-consuming tasks such as handover, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0156] Recent attempts to integrate AI into wireless communication systems have focused on the application layer and network layer, particularly deep learning in wireless resource management and allocation. However, this research is increasingly evolving to the MAC layer and physical layer, with attempts to combine deep learning with wireless transmission, particularly in the physical layer. AI-based physical layer transmission refers to applying AI-based signal processing and communication mechanisms, rather than traditional communication frameworks, in the fundamental signal processing and communication mechanisms. For example, this may include deep learning-based channel coding and decoding, deep learning-based signal estimation and detection, deep learning-based multiple input multiple output (MIMO) mechanisms, and AI-based resource scheduling and allocation.

[0157] Machine learning can be used for channel estimation and channel tracking, as well as for power allocation and interference cancellation at the physical layer of the downlink (DL). Machine learning can also be used for antenna selection, power control, and symbol detection in MIMO systems.

[0158] However, the application of DNN for transmission at the physical layer may have the following problems.

[0159] Deep learning-based AI algorithms require a large amount of training data to optimize training parameters. However, due to limitations in obtaining training data from specific channel environments, a large amount of training data is used offline. This means that static training on training data in specific channel environments can lead to conflicts with the dynamic characteristics and diversity of the wireless channel.

[0160] Furthermore, current deep learning primarily targets real-world signals. However, signals at the physical layer of wireless communications are complex signals. Further research is needed on neural networks capable of detecting complex domain signals to match the characteristics of wireless communication signals.

[0161] Below, we will look at machine learning in more detail.

[0162] Machine learning refers to a series of operations that train machines to perform tasks that humans can or cannot perform. Machine learning requires data and a learning model. In machine learning, data learning methods can be broadly categorized into three types: supervised learning, unsupervised learning, and reinforcement learning.

[0163] Neural network training aims to minimize output errors. It involves repeatedly inputting training data into a neural network, calculating the neural network output and target error for the training data, and backpropagating the neural network error from the output layer to the input layer to update the weights of each node in the neural network to reduce the error.

[0164] Supervised learning uses labeled training data, while unsupervised learning may not have labeled training data. For example, in the case of supervised learning for data classification, the training data may be data in which each training data category is labeled. The labeled training data is input to a neural network, and the error can be calculated by comparing the output (categories) of the neural network with the training data labels. The calculated error is backpropagated through the neural network in the backward direction (i.e., from the output layer to the input layer), and the connection weights of each node in each layer of the neural network can be updated through backpropagation. The amount of change in the connection weights of each updated node can be determined by the learning rate. The neural network's calculation of the input data and the backpropagation of the error can constitute a learning cycle (epoch). The learning rate can be applied differently depending on the number of iterations of the neural network's learning cycle. For example, in the early stages of training a neural network, a high learning rate can be used to quickly allow the network to achieve a certain level of performance, thereby increasing efficiency. In the later stages of training, a low learning rate can be used to increase accuracy.

[0165] Learning methods may vary depending on the characteristics of the data. For example, if the goal is to accurately predict data transmitted by a transmitter in a communication system, supervised learning is preferable to unsupervised learning or reinforcement learning.

[0166] The learning model corresponds to the human brain, and the most basic linear model can be thought of, but the machine learning paradigm that uses highly complex neural network structures, such as artificial neural networks, as learning models is called deep learning.

[0167] The neural network cores used in learning methods are largely divided into deep neural networks (DNN), convolutional deep neural networks (CNN), and recurrent Boltzmann machines (RNN), and these learning models can be applied.

[0168] An artificial neural network is an example of a network of multiple perceptrons.

[0169] Figure 10 shows an example of a perceptron structure.

[0170] Referring to Fig. 10, when the input vector x=(x1,x2,...,xd) is input, each component is multiplied by the weight (W1,W2,...,Wd), and all the results are added up, and then the activation function σ( ) is called a perceptron. A large artificial neural network structure can extend the simplified perceptron structure shown in Fig. 10 to apply input vectors to different multi-dimensional perceptrons. For convenience of explanation, input values ​​or output values ​​are called nodes.

[0171] Meanwhile, the perceptron structure illustrated in Fig. 10 can be explained as consisting of a total of three layers based on input and output values. An artificial neural network in which there are H perceptrons of (d+1) dimensions between the 1st layer and the 2nd layer, and K perceptrons of (H+1) dimensions between the 2nd layer and the 3rd layer can be expressed as in Fig. 4. Fig. 11 shows an example of a multilayer perceptron structure.

[0172] The layer where the input vector is located is called the input layer, the layer where the final output value is located is called the output layer, and all layers located between the input layer and the output layer are called hidden layers. The example in Fig. 4 discloses three layers, but when counting the number of layers in an actual artificial neural network, the input layer is excluded, so it can be viewed as a total of two layers. An artificial neural network is composed of perceptrons, which are basic blocks, connected in two dimensions.

[0173] The aforementioned input, hidden, and output layers can be applied jointly not only to multilayer perceptrons but also to various artificial neural network structures, such as CNNs and RNNs, which will be described later. The greater the number of hidden layers, the deeper the artificial neural network. The machine learning paradigm that uses sufficiently deep artificial neural networks as learning models is called deep learning. Furthermore, the artificial neural network used for deep learning is called a deep neural network (DNN).

[0174] The deep neural network illustrated in Figure 12 is a multilayer perceptron consisting of eight hidden layers and eight output layers. The multilayer perceptron structure is referred to as a fully connected neural network. In a fully connected neural network, there is no connection between nodes located in the same layer, and there is a connection only between nodes located in adjacent layers. DNN has a fully connected neural network structure and is composed of a combination of multiple hidden layers and activation functions, and can be usefully applied to identify correlation characteristics between inputs and outputs. Here, the correlation characteristic can mean the joint probability of inputs and outputs.

[0175] Meanwhile, depending on how multiple perceptrons are connected to each other, various artificial neural network structures different from the aforementioned DNN can be formed.

[0176] In DNN, nodes located within a single layer are arranged in a one-dimensional vertical direction. However, Fig. 13 can assume a case where nodes are arranged two-dimensionally, with w nodes in width and h nodes in height (convolutional neural network structure of Fig. 6). In this case, since a weight is added to each connection in the connection process from one input node to the hidden layer, a total of h×w weights must be considered. Since there are h×w nodes in the input layer, a total of h2w2 weights are required between two adjacent layers.

[0177] The convolutional neural network of Fig. 13 has a problem in that the number of weights increases exponentially according to the number of connections. Therefore, instead of considering the connections of all modes between adjacent layers, it assumes that there are small filters, and performs weighted sum and activation function operations on the overlapping portions of the filters, as in Fig. 7.

[0178] Each filter has a weight corresponding to its size, and weight learning can be performed to extract and output a specific feature on the image as a factor. In Fig. 14, a 3×3 filter is applied to the upper left 3×3 region of the input layer, and the output value resulting from performing weighted sum and activation function operations on the corresponding node is stored in z22.

[0179] The above filter performs weighted sum and activation function operations while moving at a certain horizontal and vertical interval while scanning the input layer, and places the output value at the current filter position. This operation method is similar to the convolution operation for images in the field of computer vision, so a deep neural network with this structure is called a convolutional neural network (CNN), and the hidden layer generated as a result of the convolution operation is called a convolutional layer. In addition, a neural network with multiple convolutional layers is called a deep convolutional neural network (DCNN).

[0180] In the convolutional layer, the number of weights can be reduced by calculating a weighted sum that includes only the nodes located in the area covered by the filter, starting from the node where the current filter is located. This allows a single filter to focus on features within a local area. Accordingly, CNNs can be effectively applied to image data processing where physical distance in a two-dimensional area is an important criterion for judgment. Meanwhile, CNNs can apply multiple filters immediately before the convolutional layer, and can generate multiple output results through the convolution operation of each filter.

[0181] Meanwhile, depending on the data properties, there may be data for which sequence characteristics are important. Considering the length variability and chronological relationship of such sequence data, a structure that applies a method of inputting one element of the data sequence at each timestep and inputting the output vector (hidden vector) of the hidden layer output at a specific timestep together with the immediately following element in the sequence is called a recurrent neural network structure.

[0182] Figure 15 shows an example of a neural network structure in which a recurrent loop exists.

[0183] Referring to Figure 15, a recurrent neural network (RNN) is a structure that inputs elements (x1(t), x2(t), ,..., xd(t)) of a data sequence at a time point t into a fully connected neural network, and then inputs the hidden vectors (z1(t-1), z2(t-1),..., zH(t-1)) of the immediately preceding time point t-1 together and applies a weighted sum and activation function. The reason for transmitting the hidden vector to the next time point in this way is because the information in the input vectors of the preceding time points is considered to be accumulated in the hidden vector of the current time point.

[0184] Figure 16 shows an example of the operating structure of a recurrent neural network.

[0185] Referring to Figure 16, the recurrent neural network operates in a predetermined order of time for the input data sequence.

[0186] When the input vector (x1(t), x2(t), ,..., xd(t)) at time point 1 is input to the recurrent neural network, the hidden vector (z1(1), z2(1),..., zH(1)) is input together with the input vector (x1(2), x2(2),..., xd(2)) at time point 2, and the vector (z1(2), z2(2),..., zH(2)) of the hidden layer is determined through a weighted sum and an activation function. This process is repeatedly performed until time points 2, 3, ,,, T.

[0187] Meanwhile, when multiple hidden layers are placed within a recurrent neural network, it is called a deep recurrent neural network (DRNN). Recurrent neural networks are designed to be useful for processing sequence data (e.g., natural language processing).

[0188] It is a neural network core used in a learning manner, and includes various deep learning techniques such as DNN, CNN, RNN, Restricted Boltzmann Machine (RBM), Deep Belief Network (DBN), and Deep Q-Network, and can be applied to fields such as computer vision, speech recognition, natural language processing, and speech / signal processing.

[0189] Recent attempts to integrate AI into wireless communication systems have focused on the application layer, network layer, and especially deep learning in wireless resource management and allocation. However, this research is increasingly evolving to the MAC layer and physical layer, with attempts to combine deep learning with wireless transmission, particularly at the physical layer. AI-based physical layer transmission refers to the application of AI-based signal processing and communication mechanisms, rather than traditional communication frameworks, in the fundamental signal processing and communication mechanisms. For example, this may include deep learning-based channel coding and decoding, deep learning-based signal estimation and detection, deep learning-based MIMO mechanisms, and AI-based resource scheduling and allocation.

[0190] THz (Terahertz) communication

[0191] THz communications can be applied in 6G systems. For example, data transmission rates can be increased by increasing bandwidth. This can be achieved by using sub-THz communications with wide bandwidths and applying advanced massive MIMO technology.

[0192] Figure 17 is a diagram illustrating the electromagnetic spectrum applicable to the present specification. For example, referring to Figure 17, THz waves, also known as sub-millimeter radiation, generally represent a frequency band between 0.1 THz and 10 THz with a corresponding wavelength ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (Sub-THz band) is considered a major portion of the THz band for cellular communications. Adding the Sub-THz band to the mmWave band will increase the capacity of 6G cellular communications. Among the defined THz bands, 300 GHz to 3 THz is in the far infrared (IR) frequency band. Although the 300 GHz to 3 THz band is part of the optical band, it is at the boundary of the optical band and immediately follows the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0193] Key characteristics of THz communications include (i) the widely available bandwidth to support very high data rates and (ii) the high path loss that occurs at high frequencies (requiring highly directional antennas). The narrow beamwidths generated by highly directional antennas reduce interference. The small wavelength of THz signals allows for a significantly larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array technologies to overcome range limitations.

[0194] optical wireless technology

[0195] Optical wireless communication (OWC) technology is planned for 6G communications, in addition to RF-based communications for all possible device-to-access networks. These networks connect to network-to-backhaul / fronthaul networks. OWC technology has already been used in 4G communication systems, but it will be used more widely to meet the demands of 6G communication systems. OWC technologies such as light fidelity, visible light communication, optical camera communication, and wideband-based free space optical (FSO) communication are already well-known. Optical wireless communication can provide very high data rates, low latency, and secure communications. Light detection and ranging (LiDAR) can also be used for ultra-high-resolution 3D mapping in 6G communications based on wideband technology.

[0196] FSO backhaul network

[0197] The transmitter and receiver characteristics of an FSO system are similar to those of a fiber-optic network. Therefore, data transmission in an FSO system is similar to that of a fiber-optic system. Therefore, FSO can be a promising technology for providing backhaul connectivity in 6G systems, in conjunction with fiber-optic networks. Using FSO, ultra-long-distance communications are possible, even over distances exceeding 10,000 km. FSO supports high-capacity backhaul connectivity for remote and non-remote areas, such as the ocean, space, underwater, and isolated islands. FSO also supports cellular base station connections.

[0198] Massive MIMO technology

[0199] One of the key technologies for improving spectral efficiency is the application of MIMO technology. As MIMO technology improves, spectral efficiency also improves. Therefore, massive MIMO technology will be crucial in 6G systems. Because MIMO technology utilizes multiple paths, multiplexing technology must be considered to ensure that data signals can be transmitted along more than one path, as well as beam generation and operation technologies suitable for the THz band.

[0200] Blockchain

[0201] Blockchain will become a crucial technology for managing massive amounts of data in future communication systems. Blockchain is a form of distributed ledger technology. A distributed ledger is a database distributed across numerous nodes or computing devices. Each node replicates and stores an identical copy of the ledger. Blockchains are managed by a peer-to-peer (P2P) network and can exist without being managed by a central authority or server. Data on a blockchain is collected and organized into blocks. Blocks are linked together and protected using cryptography. Blockchain perfectly complements large-scale IoT with its inherently enhanced interoperability, security, privacy, reliability, and scalability. Therefore, blockchain technology offers several features, such as interoperability between devices, traceability of large amounts of data, autonomous interaction with other IoT systems, and the massive connectivity stability of 6G communication systems.

[0202] 3D networking

[0203] 6G systems integrate terrestrial and airborne networks to support vertically expanded user communications. 3D BS will be provided via low-orbit satellites and UAVs. Adding a new dimension in altitude and associated degrees of freedom, 3D connections differ significantly from existing 2D networks.

[0204] Quantum communication

[0205] Unsupervised reinforcement learning holds promise in the context of 6G networks. Supervised learning approaches cannot label the massive amounts of data generated by 6G networks. Unsupervised learning does not require labeling. Therefore, this technology can be used to autonomously build representations of complex networks. Combining reinforcement learning and unsupervised learning allows for truly autonomous network operation.

[0206] drone

[0207] Unmanned aerial vehicles (UAVs), or drones, will be a key element in 6G wireless communications. In most cases, high-speed wireless connections will be provided using UAV technology. Base stations are installed on UAVs to provide cellular connectivity. UAVs offer specific capabilities not found in fixed base station infrastructure, such as easy deployment, robust line-of-sight links, and controlled mobility. During emergencies such as natural disasters, deploying terrestrial communications infrastructure is not economically feasible, and sometimes, volatile environments make it impossible to provide services. UAVs can easily handle these situations. UAVs will become a new paradigm in wireless communications. This technology facilitates three fundamental requirements for wireless networks: enhanced mobile broadband (eMBB), URLLC, and mMTC. UAVs can also support various purposes, such as enhancing network connectivity, fire detection, disaster emergency services, security and surveillance, pollution monitoring, parking monitoring, and accident monitoring. Therefore, UAV technology is recognized as one of the most important technologies for 6G communications.

[0208] cell-free communication

[0209] Tight integration of multiple frequencies and heterogeneous communication technologies is crucial in 6G systems. As a result, users will be able to seamlessly move from one network to another without requiring any manual configuration on their devices. The best network will be automatically selected from available communication technologies. This will break the limitations of the cell concept in wireless communications. Currently, user movement from one cell to another in dense networks results in excessive handovers, resulting in handover failures, handover delays, data loss, and a ping-pong effect. 6G cell-free communications will overcome all of these challenges and provide better QoS. Cell-free communications will be achieved through multi-connectivity and multi-tier hybrid technologies, as well as heterogeneous radios on devices.

[0210] Wireless Information and Energy Transfer (WIET)

[0211] WIET uses the same fields and waves as wireless communication systems. Specifically, sensors and smartphones will be charged using wireless power transfer during communication. WIET is a promising technology for extending the life of battery-powered wireless systems. Therefore, battery-less devices will be supported by 6G communications.

[0212] Integration of sensing and communication

[0213] Autonomous wireless networks are capable of continuously sensing dynamically changing environmental conditions and exchanging information between different nodes. In 6G, sensing will be tightly integrated with communications to support autonomous systems.

[0214] Integration of Access Backhaul Networks

[0215] In 6G, the density of access networks will be enormous. Each access network will be connected to backhaul connections, such as fiber optics and FSO networks. To accommodate the massive number of access networks, there will be tight integration between access and backhaul networks.

[0216] Holographic beamforming

[0217] Beamforming is a signal processing procedure that adjusts an antenna array to transmit a wireless signal in a specific direction. It is a subset of smart antennas or advanced antenna systems. Beamforming technology offers several advantages, including high signal-to-noise ratio, interference avoidance and rejection, and high network efficiency. Holographic beamforming (HBF) is a novel beamforming method that differs significantly from MIMO systems because it uses software-defined antennas. HBF will be a highly effective approach for efficient and flexible signal transmission and reception in multi-antenna communication devices in 6G.

[0218] Big data analysis

[0219] Big data analytics is a complex process for analyzing diverse, large-scale data sets, or "big data." This process uncovers hidden data, unknown correlations, and customer trends, ensuring complete data management. Big data is collected from various sources, such as video, social networks, images, and sensors. This technology is widely used to process massive amounts of data in 6G systems.

[0220] large intelligent surface (LIS)

[0221] THz band signals have strong linearity, which can create many shadow areas due to obstacles. LIS technology, which enables expanded communication coverage, enhanced communication stability, and additional value-added services by installing LIS near these shadow areas, is becoming increasingly important. LIS is an artificial surface made of electromagnetic materials that can alter the propagation of incoming and outgoing radio waves. While LIS may be viewed as an extension of Massive MIMO, it differs from Massive MIMO in its array structure and operating mechanism. Furthermore, LIS operates as a reconfigurable reflector with passive elements, passively reflecting signals without using active RF chains, which offers the advantage of low power consumption. Furthermore, because each passive reflector in LIS must independently adjust the phase shift of the incoming signal, this can be advantageous for wireless communication channels. By appropriately adjusting the phase shift via the LIS controller, the reflected signal can be collected at the target receiver to boost the received signal power.

[0222] Terahertz (THz) wireless communications

[0223] Fig. 18 is a diagram illustrating a THz communication method applicable to this specification.

[0224] Referring to Fig. 18, THz wireless communication is a wireless communication using THz waves with a frequency of approximately 0.1 to 10 THz (1 THz = 1012 Hz), and may refer to terahertz (THz) band wireless communication using a very high carrier frequency of 100 GHz or higher. THz waves are located between the RF (Radio Frequency) / millimeter (mm) and infrared bands, and (i) compared to visible light / infrared rays, they penetrate non-metallic / non-polarizable materials well, and compared to RF / millimeter waves, they have a shorter wavelength, so they have high straightness and can focus beams.

[0225] In addition, since the photon energy of THz waves is only a few meV, it has the characteristic of being harmless to the human body. The frequency band expected to be used for THz wireless communication may be the D-band (110 GHz to 170 GHz) or H-band (220 GHz to 325 GHz) bands where propagation loss due to absorption of molecules in the air is small. In addition to 3GPP, standardization discussions for THz wireless communication are being centered around the IEEE 802.15 THz WG (working group), and standard documents issued by the IEEE 802.15 TG (task group) (e.g., TG3d, TG3e) may specify or supplement the contents described in this specification. THz wireless communication can be applied to wireless cognition, sensing, imaging, wireless communication, THz navigation, etc.

[0226] Specifically, referring to FIG. 18, THz wireless communication scenarios can be categorized into macro networks, micro networks, and nanoscale networks. In macro networks, THz wireless communication can be applied to vehicle-to-vehicle (V2V) connections and backhaul / fronthaul connections. In micro networks, THz wireless communication can be applied to fixed point-to-point or multi-point connections, such as wireless connections in indoor small cells and data centers, and near-field communication, such as kiosk downloading. Table 5 below shows examples of technologies that can be utilized in THz waves.

[0227] [Table 5]

[0228]

[0229] FIG. 19 is a diagram illustrating a THz wireless communication transceiver applicable to the present specification.

[0230] Referring to Figure 19, THz wireless communication can be classified based on the method for THz generation and reception. THz generation methods can be classified into optical or electronic device-based technologies.

[0231] Here, methods for generating THz using electronic components include a method using a semiconductor component such as a resonant tunneling diode (RTD), a method using a local oscillator and a multiplier, a MMIC (monolithic microwave integrated circuit) method using an integrated circuit based on a compound semiconductor HEMT (high electron mobility transistor), and a method using an Si-CMOS-based integrated circuit. In the case of Fig. 19, a multiplier (doubler, tripler, multiplier) is applied to increase the frequency, and it passes through a subharmonic mixer and is radiated by an antenna. Since the THz band forms a high frequency, a multiplier is essential. Here, the multiplier is a circuit that has an output frequency that is N times that of the input, and matches it to the desired harmonic frequency and filters out all remaining frequencies. In addition, beamforming can be implemented by applying an array antenna or the like to the antenna of Fig. 19. In Figure 19, IF represents intermediate frequency, tripler and multipler represent multipliers, PA represents a power amplifier, LNA represents a low noise amplifier, and PLL represents a phase-locked loop.

[0232] FIG. 20 is a diagram illustrating a THz signal generation method applicable to the present specification. FIG. 21 is a diagram illustrating a wireless communication transceiver applicable to the present specification.

[0233] Referring to FIGS. 20 and 21, optical device-based THz wireless communication technology refers to a method of generating and modulating a THz signal using an optical device. The optical device-based THz signal generation technology is a technology that generates an ultra-high-speed optical signal using a laser and an optical modulator, and converts it into a THz signal using an ultra-high-speed photodetector. Compared to a technology that uses only electronic devices, this technology makes it easy to increase the frequency, enables high-power signal generation, and obtains a flat response characteristic in a wide frequency band. In order to generate a THz signal based on an optical device, a laser diode, a wideband optical modulator, and an ultra-high-speed photodetector are required, as illustrated in FIG. 20. In the case of FIG. 20, the light signals of two lasers with different wavelengths are combined to generate a THz signal corresponding to the wavelength difference between the lasers. In Fig. 20, an optical coupler refers to a semiconductor device that transmits an electrical signal using optical waves to provide electrical isolation and coupling between circuits or systems, and a uni-travelling carrier photo-detector (UTC-PD) is a type of photodetector that uses electrons as active carriers and reduces the travel time of electrons by bandgap grading. The UTC-PD is capable of detecting light at 150 GHz or higher. In Fig. 20, an erbium-doped fiber amplifier (EDFA) represents an erbium-doped fiber amplifier, a photodetector (PD) represents a semiconductor device that can convert an optical signal into an electrical signal, an OSA represents an optical sub-assembly that modularizes various optical communication functions (e.g., photoelectric conversion, electro-optical conversion, etc.) into a single component, and a DSO represents a digital storage oscilloscope.

[0234] Fig. 22 is a diagram illustrating a transmitter structure applicable to the present specification. In addition, Fig. 23 is a diagram illustrating a modulator structure applicable to the present specification.

[0235] Referring to FIGS. 22 and 23, a signal phase, etc. can generally be changed by passing an optical source of a laser through an optical wave guide. At this time, data is loaded by changing the electrical characteristics through a microwave contact, etc. Therefore, the optical modulator output is formed as a modulated waveform. An opto-electrical (O / E) converter can generate a THz pulse according to an optical rectification operation by a nonlinear crystal, an opto-electrical conversion by a photoconductive antenna, an emission from a bunch of relativistic electrons, etc. A terahertz pulse (THz pulse) generated in the above manner can have a length in units of femtoseconds to picoseconds. An optical / electronic converter (O / E converter) performs down conversion by utilizing the non-linearity of the device.

[0236] Considering the THz spectrum usage, it is likely that THz systems will use multiple contiguous gigahertz bands for fixed or mobile service purposes. Based on the outdoor scenario criteria, the available bandwidth can be classified based on the oxygen attenuation of 10^2 dB / km in the spectrum up to 1 THz. Accordingly, a framework in which the available bandwidth is composed of multiple band chunks can be considered. As an example of the above framework, if the THz pulse length for one carrier is set to 50 ps, ​​the bandwidth (BW) becomes approximately 20 GHz.

[0237] Effective down-conversion from the infrared band to the terahertz band (THz band) depends on how to utilize the nonlinearity of the optical / electrical converter (O / E converter). In other words, to down-convert to the desired terahertz band (THz band), it is necessary to design an O / E converter with the most ideal non-linearity for transferring to the corresponding terahertz band (THz band). If an O / E converter that is not suitable for the target frequency band is used, errors are likely to occur in the amplitude and phase of the corresponding pulse.

[0238] In a single-carrier system, a terahertz transmission and reception system can be implemented using a single optical-to-electrical converter. Depending on the channel environment, in a multi-carrier system, the number of optical-to-electrical converters may be equal to the number of carriers. This phenomenon will be particularly noticeable in a multi-carrier system that utilizes multiple broadbands according to the aforementioned spectrum usage plan. In this regard, a frame structure for the multi-carrier system may be considered. A signal down-converted using an optical-to-electrical converter may be transmitted in a specific resource region (e.g., a specific frame). The frequency domain of the specific resource region may include a plurality of chunks. Each chunk may be composed of at least one component carrier (CC).

[0239] Here, the wireless communication technology implemented in the wireless devices (200a, 200b) of the present specification may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices (XXX, YYY) of the present specification may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (200a, 200b) of the present specification can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0240] Contents related to this disclosure

[0241] Symbols / Abbreviations / Terms

[0242] The symbols / abbreviations / terms used in this disclosure are as follows.

[0243] - BS: base station

[0244] - DCI: Downlink Control Information

[0245] - SSB: Synchronization signal block

[0246] - PBCH: Physical Broadcasting Channel

[0247] - MIB: Master information block

[0248] - Rach: Random access channel

[0249] Background technology

[0250] Path loss, commonly called propagation path loss, can be expressed as in the following mathematical equation 1.

[0251] [Mathematical Formula 1]

[0252] Pathloss = FreeSpacePathLoss+10log(d)+AT[dB] +shadow fading

[0253] In Equation 1, FreeSpacePathLoss may be the propagation path loss in free space, d may be the distance between the base station and the terminal, AT may be the additional loss due to other environmental factors such as obstacles, and shadow fading may be a random component that models the change in signal strength due to multipath propagation, environmental changes, and other random factors.

[0254] The propagation path loss in free space can be expressed as in the following mathematical equation 2.

[0255] [Equation 2]

[0256]

[0257] In mathematical expression 2, can be the propagation path loss in free space, Mutiplexed layers can be the number of multiplexed layers, bandwidth can be the bandwidth, Signal power can be the transmission power, Beamforming gain can be the beamforming gain, N0 can be ~, and PathLoss can be the path loss.

[0258] Referring to Equations 1 and 2, the propagation path loss in free space can increase depending on the center frequency, i.e., the frequency used, and the path loss can increase as the distance increases.

[0259] In wireless communications in environments with severe path loss, such as THz (Terahertz) band communications, one of the ways to overcome path loss is to configure the transmitter and receiver with a large number of antenna elements to maximize beam gain. To increase beam gain, there may be a method to increase beamforming gain by integrating many antenna elements into a single panel. However, the beam has the characteristic of becoming sharper as the number of antenna elements increases. For example, the beam width can be determined in the following way.

[0260] Fig. 24 is a diagram illustrating an example of a method for determining a beam width in a wireless communication system. Fig. 25 is a diagram illustrating an example of a case where beam alignment is not correct in a wireless communication system.

[0261] Referring to Figures 24 and 25, the angle of elevation of the beam in Figure 24 is 90 oIt can be. The beam width can be generally determined based on the half power beam width (HPBW). Here, the half power beam width can be the width between the left beam and the right beam with a power 3 dB lower than the maximum gain. The half power beam width can be determined based on the following mathematical expression 3.

[0262] [Equation 3]

[0263]

[0264] In mathematical expression 3, HPBW can be the half power beam width, can be the frequency number, N can be the number of antennas, d can be the spacing of the antennas, can be the angle of elevation of the beam. For example, as shown in Fig. 24, the angle of elevation of the beam is 90 o , and the panel contains 64*64 antenna elements, In this case, the half power beam width is 1.5 o It could be.

[0265] A base station can broadcast a synchronization signal block (SSB) at a 20ms cycle. Broadcasting can mean transmitting the same signal to all terminals within the base station's cell coverage. Assuming a beam width of 1.5 degrees, a base station would need to manage 360 / 1.5 = 240 beams to broadcast SSB.

[0266] When power is applied to a terminal, the terminal may search for an SSB to access a cell. The SSB may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). In this case, the terminal may fix the reception beam in one direction and search for an SSB until the PSS of the SSB is measured. After that, the terminal may decode the PBCH with the SSB with the highest reference signal received power (RSRP) among the searched SSBs, and then perform the remaining minimum system information (RMSI) and RACH procedures. Although the terminal may logically assume that it is aligned with the beam corresponding to the SSB index, in reality, misalignment may occur, as shown in FIG. 25. In such a case, the beamforming gain parameter in Equation 2 described above may be affected.

[0267] That is, if the conventional beam refinement operation performed after the initial cell search can be performed before the cell search, there may be an advantage of enhanced cell coverage based on better beamforming gain. The conventional beam refinement operation may be as follows.

[0268] Conventional beam refinement operation

[0269] In the preceding initial cell search operation, the transmission and reception of the random access response (RAR) message and operations up to MSG3 are omitted. The terminal can receive MSG4 from the base station within 4 ms after transmitting MSG3 to the base station. If the terminal receives MSG4 (i.e., RRC configuration), it is designed to perform the beam refinement procedure through the CSI-RS configuration in ServingCellConfigCommon in CellGroupConfig.

[0270] Frequency angle dependent beam angle variation characteristics

[0271] Fig. 26 is a drawing illustrating an example in which a beam angle is adjusted according to the position of a frequency in a wireless communication system.

[0272] Referring to Figure 26, beamforming based on a phased array can form a beam in the direction of a desired angle by linearly adding phase values ​​for each antenna element. This method is designed based on the center frequency, but the position of the carrier of the actual transmitted signal may be spaced apart from the center frequency by a certain interval. Since the phase component varies depending on the frequency position, the longer the offset interval from the center frequency, the more the beam is generated in a form in which an additional phase component is added to the phase component by the phased array, so the beam may be slightly steered compared to the desired beam angle. In the existing NR, since a narrow band was used as the channel bandwidth, this phenomenon did not affect the overall performance, so this beam steer could be ignored. However, in the higher intermediate band (e.g., 7 to 12 GHz) or the THz band, the beam width becomes narrower as described above and a wideband (e.g., 2 GHz or more) can be utilized, so problems due to this beam steer may arise. The problem of adjusting these beams can be formulated as shown in the following mathematical expression 4.

[0273] [Equation 4]

[0274]

[0275] In mathematical expression 4, Peak gain angle is the peak gain phase and may be an adjusted beam angle, fm is the carrier position of the actual transmitted signal, fc is the center frequency, can be a desired beam angle by phase array.

[0276] Referring to mathematical expression 4, if the center frequency is 150 GHz, the carrier positions of the actually transmitted signal are 155 GHz and 145 GHz, and the desired beam angle by the phased array is 60 degrees, a beam steering phenomenon of about 0.5 degrees can occur.

[0277] In this method, the desired angles at which the degree of misalignment of the beam angle adjustment is most severe can be 45 degrees, 135 degrees, 225 degrees, and 315 degrees. For example, if the desired angle is 45 degrees, a beam adjustment phenomenon of approximately 1.9 degrees can occur. Assuming a beam width of 1.5 degrees in the 64 antenna elements described above, the beam adjustment can be fully controlled depending on the position of the signal transmitting the beam in the frequency domain.

[0278] Fig. 27 is a diagram illustrating an example of beam gain due to beam misalignment according to the number of antennas in a wireless communication system.

[0279] Figure 27 is a diagram showing an example of the gain of the beam to be adjusted when the antenna elements are 32 * 1 and 2 * 1, the center frequency is 150 GHz, and the desired angle is 50 degrees.

[0280] There may be a way to enhance beam steering by utilizing passive time delay (TTD) elements. For example, within a limited bandwidth of 200 MHz, the angle that can be adjusted without true time delay (TTD) may be very small. However, utilizing TTD may allow for desired angle steering. However, the additional TTD elements required may incur hardware insertion loss and additional complexity.

[0281] The adjustment angle of the peak gain angle by TDD can be expressed as in the following mathematical expression 5.

[0282] [Equation 5]

[0283]

[0284] In mathematical expression 5, Peak gain angle can be an adjustment angle of the peak gain angle according to the tau value by TDD, c can be the speed of light, f_offset can be a value obtained by subtracting the center frequency from Fm, M can be the number of antenna elements, and D can be the spacing between antenna elements. Hereinafter, the phenomenon in which the peak gain angle of a beam changes depending on the position of the frequency can be referred to as a frequency dependent beam (FDB).

[0285] Detailed description of the present disclosure

[0286] FIG. 28 is a diagram illustrating an example of an overall procedure according to an embodiment of the present disclosure. FIG. 29 is a diagram illustrating an example of an SSB signal broadcasting method according to an embodiment of the present disclosure. FIG. 30 is a diagram illustrating an example of pilot signal mapping according to an embodiment of the present disclosure. FIGS. 31 to 32 are diagrams illustrating examples of pilot signal mapping in the time domain according to an embodiment of the present disclosure. FIG. 33 is a diagram illustrating an example of pilot signal mapping according to an embodiment of the present disclosure. FIG. 34 is a diagram illustrating an example of pilot signal mapping in the frequency domain according to an embodiment of the present disclosure. FIG. 35 is a diagram illustrating an example of frequency allocation information according to an embodiment of the present disclosure. FIGS. 36 to 38 are diagrams illustrating examples of a RACH transmission method according to an embodiment of the present disclosure. FIG. 39 is a diagram illustrating an example of a resource allocation method according to an embodiment of the present disclosure.

[0287] Referring to FIG. 28, a base station can broadcast SSB to a terminal (S2810). The base station can broadcast SSB signals based on beams. The base station can broadcast SSB through the beams illustrated in FIG. 29. Each beam can include an SSB index. The SSB index can be used by the terminal to obtain beam index information, and can be used to obtain a slot index or symbol index of an SSB transmitted when the terminal determines a downlink frame boundary, obtain monitoring slot information of PDCCH corset #0, or determine C_init in DMRS. A beam including an SSB index can be operated as a single beam.

[0288] A terminal can receive an SSB from a base station (S2810). The terminal can determine whether to perform beam refinement through an FDB based on its radio frequency (RF) capability. Meanwhile, low-end UEs may not be able to utilize an FDB that requires wideband utilization due to insufficient RF performance. Therefore, the base station can transmit to the terminal the minimum bandwidth that can use the FDB in the master information block (MIB) or system information block (SIB) 1. A procedure for determining whether the terminal can use the FDB based on its RF performance can be added as a parameter in the MIB. The terminal can acquire frequency domain resources from the master information block (MIB) included in the SSB.

[0289] The base station can transmit pilot signals, DCI, and SIB 1 to the terminal (S2820). The terminal can receive the pilot signals, DCI, and SIB 1 from the base station (S2830). The terminal can search for an optimal pilot signal among the pilot signals based on the pilot signals, DCI, and SIB 1 (S2840).

[0290] Referring to FIG. 30, in one embodiment, the base station and the terminal may transmit and receive DCI and SIB 1 after transmitting and receiving a pilot signal. Referring to FIGS. 31 and 32, in this case, corset #0, up to two SSBs, and the pilot signal may be mapped in the time domain within one slot.

[0291] Pilot signals can generally be stacked in the frequency domain. For example, if the number of multi-beams that a base station can operate is greater than or equal to the number of pilot signals due to resolution, pilot signals can be mapped to a single symbol, as shown in FIG. 32. However, if the number of multi-beams that a base station can operate is less than the number of pilots due to resolution, pilot signals can be mapped to multiple symbols, as shown in FIG. 31. Since the maximum number of symbols per SSB is 2, the base station can send pilots at maximum resolution as many as multi-beams*2. To enable this operation, an additional parameter, CandidatePilotSymbol, can be included in the MIB. CandidatePilotSymbol can be represented by the start symbol of the pilot and the allocated symbol length.

[0292] Referring to FIG. 33, in another embodiment, the base station and the terminal may transmit and receive a pilot signal after transmitting and receiving DCI and SIB 1. In this case, the CandidatePilotSymbol parameter may be included in the DCI or SIB 1. If the base station transmits a pilot signal to the terminal before the terminal transmits a RACH to the base station, more symbols may be allocated to the pilot signal.

[0293] Referring to FIG. 34, the method of allocating pilot signals in the frequency domain may vary depending on the resolution of the beam angle or the number of beams to be operated. The base station can first calculate the angle that can be adjusted to the maximum within the channel bandwidth at a specific desired angle through the above-described Equation 1. For example, assuming the channel bandwidth is 10 GHz, the usable bandwidth at the center frequency of 150 GHz may be 145 GHz to 155 GHz. If the desired beam angle through the phased array is assumed to be 45 degrees, and the base station wants to transmit three pilot signals with Tx beam gains at 0.1 degree intervals, the base station can map and transmit the pilot signals in the sections of 150 GHz, 150.2 GHz, and 150.5 GHz. The positions at which the pilot signals are transmitted in the frequency domain can be expressed as in the following Equations 6 to 9.

[0294] [Equation 6]

[0295]

[0296] [Equation 7]

[0297]

[0298] [Equation 8]

[0299]

[0300] [Equation 9]

[0301]

[0302] Referring to Equations 6 through 9, the target angle desired by the base station cannot be allocated beyond the maximum beam angle within the channel bandwidth. Since the terminal must be able to determine the interval at which the pilot signal is mapped through frequency allocation information, the pilot signal can be configured as follows.

[0303] Method 1 of assigning pilot signals

[0304] Referring to Figure 35, frequency allocation information may be included in the MIB. Since the pilot signals will be mapped at regular intervals, the frequency allocation information may only include offset values.

[0305] The interval between pilot signals is an offset, and the pilot signals have a pattern in which they are periodically mapped in a lower / higher direction relative to the center frequency. SSB resources must be located in the carrier region adjacent to the center frequency. If the frequency offset is set to 0, the UE knows that pilot signals are mapped in all bands (Full band) and can perform measurements accordingly. In this case, the UE may not consider the number of pilot signals (Num pilot). In this case, the frequency allocation information may be as shown in the following mathematical expression (10).

[0306] [Equation 10]

[0307] Frequency allocation = {num_pilot = (total number of pilot signals / 2) + 1, frequency offset}

[0308] In mathematical expression 10, Frequency allocation may be frequency allocation information, num_pilot may be the number of pilot signals, and frequency offset may be a frequency offset.

[0309] [Method 2 for assigning pilot signals]

[0310] The base station can map the pilot signal. The base station can configure parameters as shown in the following mathematical expression 11.

[0311] [Equation 11]

[0312] Frequency allocation = {num_pilot = (total number of pilots / 2) + 1, desired angle, resolution angle}

[0313] In mathematical expression 11, frequency allocation may be resource allocation information for a pilot signal, desired angle may refer to the angle at which the base station steers using the PA, and resolution angle may refer to information on the degree interval at which the base station transmits the pilot signal. The base station may transmit resource allocation information for the pilot signal to the terminal.

[0314] The terminal can receive resource allocation information for the pilot signal from the base station. The terminal can acquire pilot signal resources based on the resource allocation information. The terminal can obtain information regarding the resource blocks to which the pilot signal is mapped based on Table 6 below.

[0315] [Table 6]

[0316]

[0317] Whether a base station maps pilot signals to all bands and based on what offsets they map pilot signals can each have advantages and disadvantages. When pilot signals are mapped across the entire band, the power of each subcarrier can be evenly distributed. Therefore, when a terminal performs measurements, the beam gain per subcarrier tends to vary smoothly. Based on this, the terminal can easily find the subcarrier where the optimal beam gain is located. This method is similar to the beam refinement reference signal (BRRS). When a base station transmits pilot signals only in a portion of the entire band, resources such as PDSCH or PDCCH can be allocated to already accessed terminals in the empty resources other than those for transmitting pilot signals. However, because the pilot signal gain is not smooth and is discrete, the terminal may not perform the profile accurately.

[0318] Components of a pilot signal

[0319] A pilot signal may only contain information known between the base station and the terminal. The terminal can measure RSRP based on the pilot signal. The pilot signal may be one or more tones, and the code may be defined as a fixed, unique value.

[0320] A terminal can receive a pilot signal at a fixed angle. Therefore, when measuring RSRP at a location where the pilot signal is received, the RSRP will be measured differently because the angle dependent on each pilot signal is different.

[0321] How to assign pilot numbers to pilot signals

[0322] Referring to Figure 34, the terminal needs to distinguish the pilot index to select the RO (RACH occasion) resource. Therefore, the pilot index needs to be agreed upon in advance between the base station and the terminal. Based on the center frequency, the pilot signals transmitted on the upper carriers can be sequentially mapped, such as 1, 2, and 3, and the pilot signals transmitted on the lower carriers can be sequentially mapped, such as 4, 5, and 6. Alternatively, the number of pilot signals can be sequentially agreed upon in order from top to bottom. This method must be predefined. Alternatively, a distinction flag can be added to the frequency allocation to allow one of the two to be selected. That is, a frequency allocation information distinction flag can be added. Thereafter, the method by which the terminal receives coreset #0 and SIB 1 can be identical to the existing procedure.

[0323] The terminal can transmit a RACH to the base station (S2840). Referring to FIG. 35, in order to transmit a refined BS Tx beam to the base station through a pilot signal, the terminal must be able to transmit a RACH to the base station through a pilot signal having the largest RSRP measurement value among the pilot signals. The terminal must be able to transmit the RACH at the position of the RO (Rach occasion) where the QCL (quansi co-located) of the pilot signal having the largest RSRP measurement value is located. That is, the terminal can perform beam alignment based on the RACH position. Information about the RO resource is included in SIB1. The RO resource can be expressed as {[pilot signal number 1, RO resource information], [pilot signal number 2, RO resource information]}. The terminal can acquire and transmit the RACH resource corresponding to the number of the pilot signal at which the highest RSRP value is measured through the number of pilot signals found in advance.

[0324] Referring to FIG. 37, in one embodiment, a terminal receiving multiple pilot signals can transmit a single RACH to the terminal. The terminal can use the preamble ID within the RACH as the number of the pilot signal. For example, when setting the resolution to 0.1 degrees in a 1-degree beam, the terminal can assign a preamble ID of 1 to 10, or set the current preamble ID to 0 to 63, and the terminal can randomly select a preamble ID from 0 to 5.

[0325] Referring to FIG. 38, in one embodiment, a terminal that has received multiple pilot signals can transmit a RACH after grouping the pilot signals by two.

[0326] The base station can receive RACH from the terminal (S2840).

[0327] The base station can determine the beam alignment (S2850). Since the base station will have mapped the pilot signal based on the beam resolution in advance, it can determine which pilot signal measured the highest RSRP based on the receiving position of the RO.

[0328] The base station can transmit MSG 2 to the terminal (S2860). The terminal can receive MSG2 from the base station (S2860). The terminal can transmit MSG3 to the base station (S2870). The base station can receive MSG3 from the terminal (S2870). The base station can transmit MSG4 to the terminal (S2880). The terminal can receive MSG4 from the base station (S2880). In S2860 to S2880, MSG2 to MSG4 can be mapped near the pilot signal with the highest RSRP. That is, MSG2 to MSG4 can be transmitted through the location of the subcarrier of the pilot signal or an adjacent subcarrier. In addition, the terminal can receive MSG2 to MSG4 at the location where the corresponding pilot signal was received. Referring to FIG. 39, for example, if the terminal has the largest measurement value of RSRP of pilot signal 1, MSG2 to MSG4 can be allocated near the resource of pilot signal 1.

[0329] The base station can transmit CSI to the terminal (S2890). The terminal can receive CSI from the base station (S2890). The terminal can perform channel measurement based on the CSI (S2800).

[0330] Figure 40 is a flowchart of a signal transmission and reception method according to one embodiment of the present disclosure.

[0331] Referring to FIG. 40, a terminal may receive an SSB from a base station (S4010). The terminal may receive an SSB including an MIB from the base station. The MIB may include information about a pilot signal. The information about the pilot signal may include information about the start symbol position and symbol length of a plurality of pilot signals or frequency allocation information of the plurality of pilot signals. The frequency allocation information of the plurality of pilot signals may be determined based on the number of the plurality of pilot signals, the number of the plurality of pilot signals, information about the beam angle steered by the base station, and information about the angular interval at which the plurality of pilot signals are transmitted.

[0332] The terminal can receive multiple pilot signals, DCI, and SIB 1 from the base station (S4020). The terminal can receive multiple pilot signals based on information about the pilot signals included in the MIB.

[0333] The terminal may receive multiple pilot signals from the base station and then receive DCI and SIB 1, or may receive multiple pilot signals after receiving DCI and SIB 1 from the base station.

[0334] The terminal can select an optimal pilot signal from among multiple pilot signals (S4030). The terminal can obtain information about the pilot signal frequency resources of each of the multiple pilot signals, and can obtain information about the resource blocks to which each of the multiple pilot signals is mapped based on the information about the pilot signal frequency resources of each of the multiple pilot signals and the center frequency.

[0335] The terminal can measure the RSRP of each of the plurality of pilot signals, and select the pilot signal having the largest RSRP measurement value among the plurality of pilot signals as the optimal pilot signal.

[0336] The terminal may transmit a RACH to the base station (S4040). The terminal may further include the steps of receiving MSG 2 from the base station, transmitting MSG 3 to the base station, and receiving MSG 4 from the base station. MSG 2, MSG 3, and MSG 4 may be mapped to resources to which the optimal pilot signal is mapped or resources adjacent to the resources to which the optimal pilot signal is mapped.

[0337] FIG. 41 is a flowchart of a signal transmission and reception method according to another embodiment of the present disclosure.

[0338] Referring to FIG. 41, a base station may transmit an SSB to a terminal (S4110). The base station may transmit an SSB including an MIB to the terminal. The MIB may include information about a pilot signal. The information about the pilot signal may include information about the starting symbol position and symbol length of a plurality of pilot signals or frequency allocation information of the plurality of pilot signals. The frequency allocation information of the plurality of pilot signals may be determined based on the number of the plurality of pilot signals, the number of the plurality of pilot signals, information about the beam angle steered by the base station, and information about the angular interval at which the plurality of pilot signals are transmitted.

[0339] The base station can transmit multiple pilot signals, DCI, and SIB 1 to the terminal (S4120). The base station can transmit multiple pilot signals based on information about the pilot signals included in the MIB.

[0340] The base station may transmit multiple pilot signals to the terminal and then transmit DCI and SIB 1, or may transmit multiple pilot signals after transmitting DCI and SIB 1 to the terminal.

[0341] The base station can receive RACH from the terminal (S4130). The base station can transmit MSG 2 to the terminal, receive MSG 3 from the terminal, and transmit MSG 4 to the terminal. MSG 2, MSG 3, and MSG 4 can be mapped to resources to which the optimal pilot signal is mapped or resources adjacent to the resources to which the optimal pilot signal is mapped.

[0342] The embodiments described above are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to combine some components and / or features to form an embodiment of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the scope of the patent may be combined to form an embodiment or may be incorporated as a new claim through a post-application amendment.

[0343] Embodiments according to the present specification may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0344] When implemented via firmware or software, an embodiment of the present specification may be implemented in the form of a module, procedure, function, or the like that performs the functions or operations described above. The software code may be stored in memory and executed by a processor. The memory may be located within or external to the processor and may exchange data with the processor via various known means.

[0345] It will be apparent to those skilled in the art that this specification may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the foregoing detailed description should not be construed in any way as limiting but rather as illustrative. The scope of this specification should be determined by a reasonable interpretation of the appended claims, and all changes within the scope of equivalents herein are intended to be included within the scope of this specification.

Claims

1. In a method performed by a user equipment (UE) in a wireless communication system, A step of receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information regarding a pilot signal; A step of receiving a plurality of pilot signals, downlink control information (DCI) and system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received based on information about the pilot signals included in the MIB; A step of selecting an optimal pilot signal among the plurality of pilot signals; and A method comprising the step of transmitting, to the base station, a random access channel (RACH) in a random access channel occasion (RACH occasion) associated with the optimal pilot signal.

2. In paragraph 1, Information about the above pilot signal, A method comprising information about start symbol positions and symbol lengths of the plurality of pilot signals or frequency allocation information of the plurality of pilot signals.

3. The frequency allocation information of the above multiple pilot signals is, A method, wherein the number of the plurality of pilot signals is determined based on information about the number of the plurality of pilot signals, information about the beam angle steered by the base station, and information about the angular interval at which the plurality of pilot signals are transmitted.

4. In paragraph 1, The step of receiving the plurality of pilot signals, the DCI and the SIB 1 from the base station comprises: A step of receiving the DCI and the SIB 1 after receiving the plurality of pilot signals from the base station; or A method comprising the step of receiving the plurality of pilot signals after receiving the DCI and the SIB 1 from the base station.

5. In paragraph 1, The step of selecting the optimal pilot signal among the above multiple pilot signals is: A step of obtaining information about the pilot signal frequency resource of each of the plurality of pilot signals; and A method further comprising the step of obtaining information about a resource block to which each of the plurality of pilot signals is mapped based on information about the pilot signal frequency resources of each of the plurality of pilot signals and a center frequency.

6. In paragraph 1, The step of selecting the optimal pilot signal among the above multiple pilot signals is: A step of measuring the RSRP (reference signal received power) of each of the plurality of pilot signals; and A method comprising the step of selecting a pilot signal having the largest RSRP measurement value among the plurality of pilot signals as the optimal pilot signal.

7. In paragraph 1, A step of receiving MSG (message) 2 from the above base station; A step of transmitting MSG 3 to the above base station; and Further comprising the step of receiving MSG 4 from the base station, A method wherein the MSG 2, the MSG 3 and the MSG 4 are mapped to the resource to which the optimal pilot signal is mapped or to a resource adjacent to the resource to which the optimal pilot signal is mapped.

8. In a terminal (user equipment, UE) operating in a communication system, One or more transmitters and receivers; one or more processors controlling said one or more transceivers; and A memory comprising one or more instructions to be performed by said one or more processors, One or more of the above commands, A step of receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information regarding a pilot signal; A step of receiving a plurality of pilot signals, downlink control information (DCI) and system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received based on information about the pilot signals included in the MIB; A step of selecting an optimal pilot signal among the plurality of pilot signals; and A terminal comprising a step of transmitting a RACH (random access channel) in a RO (random access channel occasion, RACH occasion) related to the optimal pilot signal to the base station.

9. In a method of operating a base station (BS) in a wireless communication system, A step of transmitting a synchronization signal block (SSB) including a master information block (MIB) to a base station (BS) from a user equipment (UE), wherein the MIB includes information regarding a pilot signal; A step of transmitting a plurality of pilot signals, DCI (downlink control information) and SIB (system information block) 1 to the terminal, wherein the plurality of pilot signals are transmitted based on information about the pilot signals included in the MIB; and A method comprising the step of receiving a RACH (random access channel) in a RO (random access channel occasion, RACH occasion) related to an optimal pilot signal among the plurality of pilot signals from the terminal.

10. In paragraph 9, Information about the above pilot signal, A method comprising information about start symbol positions and symbol lengths of the plurality of pilot signals or frequency allocation information of the plurality of pilot signals.

11. In paragraph 10, The frequency allocation information of the above plurality of pilot signals is, A method, wherein the number of the plurality of pilot signals is determined based on information about the number of the plurality of pilot signals, information about the beam angle steered by the base station, and information about the angular interval at which the plurality of pilot signals are transmitted.

12. In paragraph 9, The step of transmitting the plurality of pilot signals, the DCI and the SIB 1 to the terminal is: A step of transmitting the DCI and the SIB 1 after transmitting the plurality of pilot signals to the terminal; or A method comprising the step of transmitting the plurality of pilot signals after transmitting the DCI and the SIB 1 to the terminal.

13. In paragraph 9, A step of transmitting MSG (message) 2 to the above terminal; A step of receiving MSG 3 from the terminal; and Further comprising the step of transmitting MSG 4 to the terminal; A method wherein the MSG 2, the MSG 3 and the MSG 4 are mapped to the resource to which the optimal pilot signal is mapped or to a resource adjacent to the resource to which the optimal pilot signal is mapped.

14. In a base station (BS) operating in a communication system, One or more transmitters and receivers; one or more processors controlling said one or more transceivers; and A memory comprising one or more instructions to be performed by said one or more processors, One or more of the above commands, A step of transmitting a synchronization signal block (SSB) including a master information block (MIB) to a base station (BS) from a user equipment (UE), wherein the MIB includes information regarding a pilot signal; A step of transmitting a plurality of pilot signals, DCI (downlink control information) and SIB (system information block) 1 to the terminal, wherein the plurality of pilot signals are transmitted based on information about the pilot signals included in the MIB; and A base station, comprising a step of receiving a RACH (random access channel) in a RO (random access channel occasion, RACH occasion) related to an optimal pilot signal among the plurality of pilot signals from the terminal.

15. A device comprising one or more memories and one or more processors functionally connected to the one or more memories, The above one or more processors are configured such that the device, A step of receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information regarding a pilot signal; A step of receiving a plurality of pilot signals, downlink control information (DCI) and system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received based on information about the pilot signals included in the MIB; A step of selecting an optimal pilot signal among the plurality of pilot signals; and A device operative to perform a step of transmitting, to the base station, a random access channel (RACH) in a RO (random access channel occasion, RACH occasion) associated with the optimal pilot signal.

16. In one or more non-transitory computer-readable media storing one or more instructions, A step of receiving a synchronization signal block (SSB) including a master information block (MIB) from a base station (BS), wherein the MIB includes information regarding a pilot signal; A step of receiving a plurality of pilot signals, downlink control information (DCI) and system information block (SIB) 1 from the base station, wherein the plurality of pilot signals are received based on information about the pilot signals included in the MIB; A step of selecting an optimal pilot signal among the plurality of pilot signals; and A computer-readable medium operable to perform a step of transmitting, to the base station, a random access channel (RACH) at a random access channel occasion (RACH occasion) associated with the optimal pilot signal.

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