Apparatus and method for transmitting signal by using metasurface installed in limited space in wireless communication system

Abstract

The purpose of the present disclosure is to transmit a signal by using a metasurface installed in a limited space in a wireless communication system, and an operation method of a first device may comprise the steps of: generating at least one sequence for a synchronization signal; generating the synchronization signal on the basis of the at least one sequence; generating a broadcast signal including system information; determining directions for transmitting the synchronization signal and the broadcast signal; and transmitting the synchronization signal and the broadcast signal in the directions.

Description

Device and method for transmitting signals using a metasurface installed in a limited space in a wireless communication system

[0001] The following description relates to a wireless communication system, and to a device and method for transmitting a signal using a metasurface installed in a limited space 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] The present disclosure can provide a device and method for effectively transmitting a signal using a metasurface in a wireless communication system.

[0005] The present disclosure can provide a device and method for transmitting a signal in a limited space using a metasurface in a wireless communication system.

[0006] The present disclosure can provide a device and method for transmitting a signal in a desired direction using a metasurface in a corridor-shaped space in a wireless communication system.

[0007] The present disclosure may provide a device and method for installing a metasurface for beamforming in a space in the form of a bent passage in a wireless communication system.

[0008] The present disclosure can provide a device and method for transmitting a signal using a plurality of metasurfaces in a space in the form of a bent passage in a wireless communication system.

[0009] The present disclosure can provide a device and method for transmitting a signal using a multi-beam formed by a metasurface in a space in the form of a bent passage in a wireless communication system.

[0010] The present disclosure may provide a device and method for utilizing multi-beams and single beams for signal transmission in a bent-path type space in a wireless communication system.

[0011] The present disclosure can provide a device and method for converting a single-beam signal into a multi-beam signal and back into a single-beam signal for signal transmission in a bent-path type space in a wireless communication system.

[0012] The present disclosure can provide a device and method for sweeping a synchronization signal using a plurality of metasurfaces in a space in the form of a bent passage in a wireless communication system.

[0013] The present disclosure can provide a device and method for sweeping a broadcast signal using a plurality of metasurfaces in a space in the form of a bent passage in a wireless communication system.

[0014] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other technical tasks not mentioned can be considered by a person having ordinary skill in the technical field to which the technical configuration of the present disclosure is applied from the embodiments of the present disclosure described below.

[0015] As an example of the present disclosure, a method of operating a first device in a wireless communication system may include the steps of generating at least one sequence for a synchronization signal, generating the synchronization signal based on the at least one sequence, generating a broadcast signal including system information, determining directions for transmitting the synchronization signal and the broadcast signal, and transmitting the synchronization signal and the broadcast signal in the directions. The synchronization signal and the broadcast signal may be transmitted from the first device located at one side of the curved passage to the second device located at the other side of the curved passage by being reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of the first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage connecting a first passage and a second passage.

[0016] As an example of the present disclosure, in a wireless communication system, a first device includes a transceiver and a processor connected to the transceiver, wherein the processor generates at least one sequence for a synchronization signal, generates the synchronization signal based on the at least one sequence, generates a broadcast signal including system information, determines directions for transmitting the synchronization signal and the broadcast signal, and controls transmission of the synchronization signal and the broadcast signal in the directions, wherein the synchronization signal and the broadcast signal are reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of a first passageway and a second RIS installed on a wall surface of the second passageway in a space in the form of a bent passageway where a first passageway and a second passageway are connected, thereby being transmitted from the first device located at one side of the bent passageway toward a second device located at the other side of the bent passageway.

[0017] As an example of the present disclosure, a communication device includes at least one processor, and at least one computer memory connected to the at least one processor and storing instructions that, when executed by the at least one processor, direct operations, wherein the operations may include: generating at least one sequence for a synchronization signal; generating the synchronization signal based on the at least one sequence; generating a broadcast signal including system information; determining directions for transmitting the synchronization signal and the broadcast signal; and transmitting the synchronization signal and the broadcast signal in the directions. The synchronization signal and the broadcast signal may be transmitted from the communication device located at one side of the curved passage to another communication device located at the other side of the curved passage by being reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of a first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage connecting a first passage and a second passage.

[0018] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction includes at least one instruction executable by a processor, the at least one instruction causing a device to generate at least one sequence for a synchronization signal, generate the synchronization signal based on the at least one sequence, generate a broadcast signal including system information, determine directions for transmitting the synchronization signal and the broadcast signal, and control the synchronization signal and the broadcast signal to be transmitted in the directions, wherein the synchronization signal and the broadcast signal can be transmitted from the device located at one side of the curved passage to another device located at the other side of the curved passage by being reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of the first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage where a first passage and a second passage are connected.

[0019] The above-described aspects of the present disclosure are only some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the present disclosure can be derived and understood by a person having ordinary skill in the art based on the detailed description of the present disclosure to be described below.

[0020] The following effects may be achieved by embodiments based on the present disclosure.

[0021] According to the present disclosure, a metasurface can be effectively utilized in a confined space such as a curved corridor.

[0022] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure is applied, from the description of the embodiments of the present disclosure below. In other words, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived from the embodiments of the present disclosure by those skilled in the art.

[0023] The accompanying drawings are intended to aid understanding of 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.

[0024] Figure 1 illustrates an example of a communication system applicable to the present disclosure.

[0025] Figure 2 illustrates an example of a wireless device applicable to the present disclosure.

[0026] FIG. 3 illustrates another example of a wireless device applicable to the present disclosure.

[0027] Figure 4 illustrates an example of a portable device applicable to the present disclosure.

[0028] FIG. 5 illustrates an example of a vehicle or autonomous vehicle applicable to the present disclosure.

[0029] Figure 6 illustrates an example of AI (Artificial Intelligence) applicable to the present disclosure.

[0030] FIG. 7 illustrates a method for processing a transmission signal applicable to the present disclosure.

[0031] FIG. 8 illustrates an example of a communication structure that can be provided in a 6G (6th generation) system applicable to the present disclosure.

[0032] Figure 9 illustrates an electromagnetic spectrum applicable to the present disclosure.

[0033] Figure 10 illustrates a THz communication method applicable to the present disclosure.

[0034] FIG. 11 illustrates examples of changes in electromagnetic waves due to a metasurface according to one embodiment of the present disclosure.

[0035] FIGS. 12A and 12B illustrate examples of situations in which a metasurface is utilized according to one embodiment of the present disclosure.

[0036] FIGS. 13A and 13B illustrate examples of metasurface and reflector array antennas according to one embodiment of the present disclosure.

[0037] Figure 14 shows a comparative graph of spectral efficiency versus surface area of ​​RIS (reconfigurable intelligent surface) and repeater technology.

[0038] FIGS. 15a and 15b illustrate examples of installation of a metasurface according to one embodiment of the present disclosure.

[0039] FIGS. 16A and 16B illustrate another installation example of a metasurface according to one embodiment of the present disclosure.

[0040] FIGS. 17A and 17B illustrate another example of installation of a metasurface according to one embodiment of the present disclosure.

[0041] Figures 18a and 18b illustrate experimental results on metasurfaces arranged according to one embodiment of the present disclosure.

[0042] FIGS. 19A and 19B illustrate examples of the shapes of beams formed from metasurfaces arranged according to one embodiment of the present disclosure.

[0043] FIGS. 20A and 20B illustrate experimental results for the directional properties of beams formed from metasurfaces arranged according to one embodiment of the present disclosure.

[0044] FIGS. 21A and 21B illustrate experimental results for EIRP of beams formed from metasurfaces arranged according to one embodiment of the present disclosure.

[0045] FIG. 22 illustrates an example of beam forming using a non-uniform phase front on a metasurface according to one embodiment of the present disclosure.

[0046] FIG. 23 illustrates an example of a structure for performing communication using RIS according to one embodiment of the present disclosure.

[0047] FIG. 24 illustrates an example of a procedure for performing an initial connection using RIS according to one embodiment of the present disclosure.

[0048] FIG. 25 illustrates an example of a procedure for transmitting a signal using RIS according to one embodiment of the present disclosure.

[0049] FIG. 26 illustrates an example of a procedure for performing multi-beam beamforming using RIS according to one embodiment of the present disclosure.

[0050] The following embodiments combine the components and features of the present disclosure 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 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.

[0051] In the description of the drawings, procedures or steps that may obscure the gist of the present disclosure are not described, and procedures or steps that can be understood by a person skilled in the art are also not described.

[0052] Throughout the specification, when a part is said to "comprising" or "including" a component, this does not mean that other components may be included, but rather that other components may be excluded, unless otherwise specifically stated. 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 the present disclosure (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.

[0053] Embodiments of the present disclosure described herein 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.

[0054] 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.

[0055] Additionally, in the embodiments of the present disclosure, 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).

[0056] 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.

[0057] Embodiments of the present disclosure 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 disclosure 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.

[0058] Furthermore, the embodiments of the present disclosure can be applied to other wireless access systems and are not limited to the systems described above. For example, they can be applied to systems implemented after the 3GPP 5G NR system and are not limited to a specific system.

[0059] That is, obvious steps or parts not described in the embodiments of the present disclosure can be explained by referring to the above documents. In addition, all terms disclosed in this document can be explained by the above standard documents.

[0060] Hereinafter, preferred embodiments according to the present disclosure 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 disclosure and is not intended to represent the only embodiments in which the technical configurations of the present disclosure may be implemented.

[0061] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding of the present disclosure, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present disclosure.

[0062] 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).

[0063] In order to clarify the following description, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical idea of ​​the present disclosure 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.

[0064] For background information, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to this disclosure. For example, reference may be made to standard documents 36.xxx and 38.xxx.

[0065] Communication system applicable to the present disclosure

[0066] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the present disclosure disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0067] 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.

[0068] FIG. 1 is a diagram illustrating an example of a communication system applied to the present disclosure.

[0069] Referring to FIG. 1, a communication system (100) applied to the present disclosure includes a wireless device, a base station, and a network. Here, the 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.

[0070] 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).

[0071] 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 communication between base stations (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, based on various proposals of the present disclosure, at least some of 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.), resource allocation processes, etc. may be performed.

[0072] Communication system applicable to the present disclosure

[0073] FIG. 2 is a diagram illustrating an example of a wireless device applicable to the present disclosure.

[0074] 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.

[0075] 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 in this document. 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 in this document. 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 the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0076] 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 in this document. 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 the 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 commands for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. 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 the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0077] 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 in this document. 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.

[0078] 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 in this document 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 document 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 document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0079] 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.

[0080] 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 document, 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 document, 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 in this document, via one or more antennas (208a, 208b). In this document, 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.

[0081] Wireless device structure applicable to the present disclosure

[0082] FIG. 3 is a diagram illustrating another example of a wireless device applied to the present disclosure.

[0083] Referring to FIG. 3, the wireless device (300) 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 (300) may include a communication unit (310), a control unit (320), a memory unit (330), and additional elements (340). The communication unit may include a communication circuit (312) and a transceiver(s) (314). For example, the communication circuit (312) may include one or more processors (202a, 202b) and / or one or more memories (204a, 204b) of FIG. 2. For example, the transceiver(s) (314) may include one or more transceivers (206a, 206b) and / or one or more antennas (208a, 208b) of FIG. 2. The control unit (320) is electrically connected to the communication unit (310), the memory unit (330), and the additional elements (340) and controls the overall operation of the wireless device. For example, the control unit (320) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (330). In addition, the control unit (320) may transmit information stored in the memory unit (330) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (310), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (330).

[0084] The additional element (340) may be configured in various ways depending on the type of the wireless device. For example, the additional element (340) 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 (300) 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.

[0085] In FIG. 3, various elements, components, units / parts, and / or modules within the wireless device (300) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (310). For example, within the wireless device (300), the control unit (320) and the communication unit (310) may be wired, and the control unit (320) and the first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (310). In addition, each element, component, unit / part, and / or module within the wireless device (300) may further include one or more elements. For example, the control unit (320) may be composed of a set of one or more processors. For example, the control unit (320) 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 (330) may be composed of RAM, DRAM (dynamic RAM), ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0086] Mobile devices to which the present disclosure applies

[0087] FIG. 4 is a drawing illustrating an example of a mobile device applied to the present disclosure.

[0088] Figure 4 illustrates an example of a mobile device applicable to the present disclosure. 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).

[0089] Referring to FIG. 4, the portable device (400) may include an antenna unit (408), a communication unit (410), a control unit (420), a memory unit (430), a power supply unit (440a), an interface unit (440b), and an input / output unit (440c). The antenna unit (408) may be configured as a part of the communication unit (410). Blocks 410 to 430 / 440a to 440c correspond to blocks 310 to 330 / 340 of FIG. 3, respectively.

[0090] The communication unit (410) can transmit and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The control unit (420) can control components of the portable device (400) to perform various operations. The control unit (420) can include an AP (application processor). The memory unit (430) can store data / parameters / programs / codes / commands required for operating the portable device (400). In addition, the memory unit (430) can store input / output data / information, etc. The power supply unit (440a) supplies power to the portable device (400) and can include a wired / wireless charging circuit, a battery, etc. The interface unit (440b) can support connection between the portable device (400) and other external devices. The interface unit (440b) can include various ports (e.g., audio input / output ports, video input / output ports) for connection with external devices. The input / output unit (440c) can input or output video information / signals, audio information / signals, data, and / or information input from a user. The input / output unit (440c) may include a camera, a microphone, a user input unit, a display unit (440d), a speaker, and / or a haptic module.

[0091] For example, in the case of data communication, the input / output unit (440c) 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 (430). The communication unit (410) 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 (410) 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 (430) and then output in various forms (e.g., text, voice, image, video, haptic) through the input / output unit (440c).

[0092] Types of wireless devices to which the present disclosure applies

[0093] FIG. 5 is a drawing illustrating an example of a vehicle or autonomous vehicle to which the present disclosure applies.

[0094] Figure 5 illustrates a vehicle or autonomous vehicle applicable to the present disclosure. The vehicle or autonomous vehicle may be implemented as a mobile robot, car, train, manned / unmanned aerial vehicle (AV), ship, etc., and is not limited to the form of a vehicle.

[0095] Referring to FIG. 5, a vehicle or autonomous vehicle (500) may include an antenna unit (508), a communication unit (510), a control unit (520), a driving unit (540a), a power supply unit (540b), a sensor unit (540c), and an autonomous driving unit (540d). The antenna unit (550) may be configured as a part of the communication unit (510). Blocks 510 / 530 / 540a to 540d correspond to blocks 410 / 430 / 440 of FIG. 4, respectively.

[0096] The communication unit (510) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations, etc.), servers, etc. The control unit (520) can control elements of a vehicle or autonomous vehicle (500) to perform various operations. The control unit (520) can include an electronic control unit (ECU).

[0097] Figure 6 is a diagram illustrating an example of an AI device applicable to the present disclosure. For example, the AI ​​device may be implemented as a fixed or mobile device, such as a TV, projector, smartphone, PC, laptop, digital broadcasting terminal, tablet PC, wearable device, set-top box (STB), radio, washing machine, refrigerator, digital signage, robot, or vehicle.

[0098] Referring to FIG. 6, the AI ​​device (600) may include a communication unit (610), a control unit (620), a memory unit (630), an input / output unit (640a / 640b), a learning processor unit (640c), and a sensor unit (640d). Blocks 610 to 630 / 640a to 640d may correspond to blocks 310 to 330 / 340 of FIG. 3, respectively.

[0099] The communication unit (610) can transmit and receive wired and wireless signals (e.g., sensor information, user input, learning models, control signals, etc.) with external devices such as other AI devices (e.g., FIG. 1, 100x, 120, 140) or AI servers (FIG. 1, 140) using wired and wireless communication technology. To this end, the communication unit (610) can transmit information within the memory unit (630) to the external device or transfer a signal received from the external device to the memory unit (630).

[0100] The control unit (620) may determine at least one executable operation of the AI ​​device (600) based on information determined or generated using a data analysis algorithm or a machine learning algorithm. In addition, the control unit (620) may control components of the AI ​​device (600) to perform the determined operation. For example, the control unit (620) may request, search, receive, or utilize data from the learning processor unit (640c) or the memory unit (630), and may control components of the AI ​​device (600) to perform a predicted operation or an operation determined to be desirable among at least one executable operation. In addition, the control unit (620) may collect history information including the operation contents of the AI ​​device (600) or user feedback on the operation, and store the collected history information in the memory unit (630) or the learning processor unit (640c), or transmit the collected history information to an external device such as an AI server (FIG. 1, 140). The collected history information may be used to update a learning model.

[0101] The memory unit (630) can store data that supports various functions of the AI ​​device (600). For example, the memory unit (630) can store data obtained from the input unit (640a), data obtained from the communication unit (610), output data of the learning processor unit (640c), and data obtained from the sensing unit (640). In addition, the memory unit (630) can store control information and / or software codes necessary for the operation / execution of the control unit (620).

[0102] The input unit (640a) can obtain various types of data from the outside of the AI ​​device (600). For example, the input unit (620) can obtain learning data for model learning, input data to which the learning model will be applied, etc. The input unit (640a) may include a camera, a microphone, and / or a user input unit. The output unit (640b) may generate output related to vision, hearing, or touch. The output unit (640b) may include a display unit, a speaker, and / or a haptic module, etc. The sensing unit (640) can obtain at least one of internal information of the AI ​​device (600), information about the surrounding environment of the AI ​​device (600), and user information using various sensors. The sensing unit (640) may include a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and / or a radar, etc.

[0103] The learning processor unit (640c) can train a model composed of an artificial neural network using learning data. The learning processor unit (640c) can perform AI processing together with the learning processor unit of the AI ​​server (Fig. 1, 140). The learning processor unit (640c) can process information received from an external device via the communication unit (610) and / or information stored in the memory unit (630). In addition, the output value of the learning processor unit (640c) can be transmitted to an external device via the communication unit (610) and / or stored in the memory unit (630).

[0104] FIG. 7 is a diagram illustrating a method for processing a transmission signal applied to the present disclosure. For example, the transmission signal may be processed by a signal processing circuit. At this time, the signal processing circuit (700) may include a scrambler (710), a modulator (720), a layer mapper (730), a precoder (740), a resource mapper (750), and a signal generator (760). At this time, as an example, the operations / functions of FIG. 7 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. 7 may be implemented in the processors (202a, 202b) and / or the transceivers (206a, 206b) of FIG. 2. As an example, blocks 710 to 760 may be implemented in the processors (202a, 202b) of FIG. 2. Additionally, blocks 710 to 750 may be implemented in the processor (202a, 202b) of FIG. 2, and block 760 may be implemented in the transceiver (206a, 206b) of FIG. 2, and are not limited to the above-described embodiment.

[0105] The codeword can be converted into a wireless signal through the signal processing circuit (700) of FIG. 7. 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). Specifically, the codeword can be converted into a bit sequence scrambled by a scrambler (710). 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 (720). 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.

[0106] A complex modulation symbol sequence can be mapped to one or more transmission layers by a layer mapper (730). The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (740) (precoding). The output z of the precoder (740) can be obtained by multiplying the output y of the layer mapper (730) 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 (740) can perform precoding after performing transform precoding (e.g., discrete Fourier transform (DFT) transform) on the complex modulation symbols. In addition, the precoder (740) can perform precoding without performing transform precoding.

[0107] The resource mapper (750) 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 (760) 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 (760) 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.

[0108] The signal processing process for receiving signals in a wireless device can be configured in reverse order of the signal processing process (710 to 760) of FIG. 7. For example, a wireless device (e.g., 200a and 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.

[0109] 6G communication system

[0110] 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 1 below. In other words, Table 1 is a table showing the requirements of the 6G system.

[0111] Per device peak data rate1 TbpsE2E latency1 msMaximum spectral efficiency100 bps / HzMobility supportup to 1000 km / hrSatellite integrationFullyAIFullyAutonomous vehicleFullyXRFullyHaptic CommunicationFully

[0112] 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.

[0113] FIG. 10 is a diagram illustrating an example of a communication structure that can be provided in a 6G system applicable to the present disclosure.

[0114] Referring to Figure 10, 6G systems are expected to have 50 times higher simultaneous wireless connectivity than 5G wireless systems. URLLC, a key feature of 5G, is expected to become a more prominent technology in 6G communications, 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.

[0115] Core implementation technology of 6G systems

[0116] - Artificial Intelligence (AI)

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] However, the application of DNN for transmission at the physical layer may have the following problems.

[0122] 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.

[0123] 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.

[0124] Below, we will look at machine learning in more detail.

[0125] 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.

[0126] 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.

[0127] 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. 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 according to the 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] THz (Terahertz) communication

[0132] 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.

[0133] FIG. 9 is a diagram illustrating an electromagnetic spectrum applicable to the present disclosure. For example, referring to FIG. 9, THz waves, also known as sub-millimeter radiation, typically 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 lies just behind the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0134] 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.

[0135] Terahertz (THz) wireless communications

[0136] FIG. 10 is a diagram illustrating a THz communication method applicable to the present disclosure.

[0137] Referring to Fig. 10, 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 enable beam focusing.

[0138] Specific embodiments of the present disclosure

[0139] The present disclosure relates to signal transmission using metasurfaces in wireless communication systems, and proposes a technique for transmitting signals using metasurfaces installed in a limited space. Furthermore, the present disclosure proposes the installation and / or arrangement of metasurfaces considering the characteristics of a given space, and describes various embodiments for transmitting signals, i.e., beamforming, based on the arrangement of the proposed metasurfaces.

[0140] Metasurfaces are a means for manipulating electromagnetic waves. They can be used to manipulate electromagnetic waves in a desired direction or to control their amplitude, phase, and optical properties. Metasurfaces generate desired electromagnetic wave patterns by manipulating electromagnetic waves. Because metasurfaces can be designed to be compact, they can help increase space efficiency and reduce installation and operating costs. Metasurfaces can be utilized in a variety of applications, and their future applications in wireless communications, radar, and sensors are expected to increase. Metasurfaces typically have optical elements with one- or two-dimensional structures. These optical elements are typically nano- or micro-sized. A device similar to a metasurface is the reconfigurable intelligent surface (RIS). An RIS consists of antenna elements that operate in the radio or microwave frequency range. The terms metasurface and RIS are sometimes used interchangeably.

[0141] A metasurface is composed of a plurality of unit cells. A unit cell may be referred to as a unit element, a meta element, a reflective element, or other terms having equivalent technical meaning. A unit cell is an element that reflects an incident signal, thereby causing a change in the state (e.g., phase and / or magnitude) of the signal. The change in the state of the signal occurring in the unit cell can be controlled according to a control signal applied to the unit cell.

[0142] As described above, a metasurface is a two-dimensional structured device that exhibits new properties other than those existing in nature, and can provide functions such as those illustrated in FIG. 11 below. FIG. 11 illustrates examples of changes in electromagnetic waves due to a metasurface according to an embodiment of the present disclosure. Referring to FIG. 11, manipulations such as polarization (1110), focusing (1120), scattering (1130), and absorption (1140) can be applied to electromagnetic waves by the metasurface. In particular, due to the increasing operating frequency band, the path loss and straightness of the beam increase, which inevitably leads to more shadow areas. Accordingly, it is not yet clear whether a new communication environment based on RIS and / or metasurfaces will be utilized in the future, or whether relay technology, which is one of the existing methods, will continue to be used. When introducing metasurfaces, cost and power consumption must also be considered from a business perspective. As frequencies increase, RF transceivers become more expensive, more difficult to implement, and consume more power. Therefore, research into the efficient use of metasurfaces and / or RIS has recently been actively underway. Furthermore, research on intelligent RIS is still in its infancy, necessitating further research and development.

[0143] FIGS. 12A and 12B illustrate examples of situations in which a metasurface is utilized according to an embodiment of the present disclosure. FIG. 12A illustrates an example of utilizing a metasurface in an outdoor environment, and FIG. 12B illustrates an example of utilizing a metasurface in an indoor environment. As shown in FIG. 12A, by installing a metasurface on an exterior wall of a building, it is possible to eliminate a base station's service shadow area or provide users with a better quality channel. Furthermore, as shown in FIG. 12B, by installing a metasurface on a wall indoors, services can be provided in all areas even in an indoor environment with many obstacles. Here, the metasurface can be used in the form of a metasurface antenna, an intelligent metasurface antenna, etc. A metasurface antenna refers to a technology that improves the basic performance of an antenna using a metasurface, a technology that modulates a frequency using a metasurface, and a technology that transmits radio waves using a metasurface. An intelligent metasurface antenna refers to a technology that performs MIMO, multiple beamforming, etc. using a metasurface.

[0144] A concept comparable to a metasurface is a reflective array antenna. FIGS. 13A and 13B illustrate examples of a metasurface and a reflective array antenna according to an embodiment of the present disclosure. Referring to FIGS. 13A and 13B , the metasurface and the reflective array antenna each include a reflector (1330), a feeder (1340), and a receiver (1350). A signal transmitted from the feeder (1340) is reflected by the reflector (1330), and the signal coverage (1342) is formed to cover the receiver (1350). A reflective array antenna having a structure like FIG. 13A is interested in how well the energy of the feeder reaches the receiver (1350). On the other hand, a metasurface / RIS is interested in how well the energy of the reflector (1330) reaches the receiver. The biggest difference between the two is the positional relationship of the feeder (1340) and the reflector (1330). Referring to Fig. 13a, the reflector array antenna has a structure in which the feeder (1340) and the reflector (1330) are co-located, and is designed based on the optimization of spillover loss and illumination loss, which represent the efficiency with which the energy of the feeder (1340) reaches the reflector (1330), and has the characteristic that the phase distribution setup itself is dependent on the feed location. On the other hand, referring to Fig. 13b, in the case of the metasurface / RIS, the feeder (1340) and the reflector (1330) are not co-located, the feeder (1340) and the reflector (1330) may be in an NLOS environment, and the phase distribution setup is independent of the feed location.Compared to reflective antenna arrays, a characteristic of RIS / metasurfaces is that when digitizing the phase distribution, a quantization lobe occurs when the number of bits is small.

[0145] When adopting a metasurface / RIS, the level of performance that must be achieved, the criteria for the performance conditions, and ultimately the size of the metasurface that must be manufactured to achieve such performance must first be examined. Figure 14 shows a graph comparing the spectral efficiency versus the surface area of ​​RIS and repeater technology. Referring to Figure 14, it can be confirmed that a metasurface with a size of approximately 1.2㎡ has a spectral efficiency equivalent to that of repeater technology. Therefore, if the size is large and the cost is lower for the equivalent performance, the metasurface / RIS can be considered a sufficiently competitive technology. This is because metasurface / RIS generally does not amplify the signal, and thus requires a much larger surface area than repeater technology to achieve a given signal quality (e.g., SNR).

[0146] To achieve performance comparable to that of repeater technology, the metasurface / RIS must be large, and implementing a PCB larger than 1.2㎡ may be difficult in manufacturing. Considering the size supported by the manufacturing equipment and the yield issues of the manufacturing equipment, there will be various issues, such as replacing the entire factory system to manufacture a PCB larger than 1.2㎡. Ultimately, to secure cost competitiveness, it is necessary to manufacture the metasurface / RIS in multiple panels, and to solve the leakage wave problem that arises due to dividing it into multiple PCBs, it is possible to implement the ground (GND), which would otherwise be divided into multiple parts, in a single part by utilizing concutive tape.

[0147] There is also the issue of installing the metasurface / RIS. The effective area of ​​the metasurface / RIS is known to be approximately ±45 degrees or ±60 degrees. This characteristic needs to be considered when installing the metasurface / RIS. The present disclosure considers a space in the shape of a corridor. The space in the shape of a corridor considered in the present disclosure can be understood as a space that includes two straight or curved corridors, and the two corridors are connected and / or joined at a certain angle (e.g., a right angle). In this space in the shape of a corridor, the metasurface can be installed in various shapes. In this case, at the boundary where the two corridors are connected, one wall of the first corridor and one wall of the second corridor form an angle, and the other wall of the first corridor and the other wall of the second corridor form another angle. At this time, the wall surfaces forming a smaller angle (e.g., less than 180°) may be referred to as outer wall surfaces, and the wall surfaces forming a larger angle (e.g., more than 180°) may be referred to as inner wall surfaces.

[0148] FIGS. 15A and 15B illustrate examples of installation of a metasurface according to one embodiment of the present disclosure. FIG. 15A illustrates an installation location of a metasurface (1530) in a space (1560), and FIG. 15B illustrates a signal transmission path according to an installation as in FIG. 15A. Referring to FIG. 15A, the metasurface (1530) may be installed at the top of a corner where two passages meet (e.g., in contact with the ceiling or at a location spaced a certain distance from the ceiling). That is, the metasurface (1530) may be installed on the outer walls of the two passages. Specifically, the metasurface (1530) may be installed such that a first corner of the metasurface (1530) contacts a wall surface of one of the two passages at a 45° angle, and a second corner of the metasurface (1530) contacts a wall surface of the other passage at a 45° angle. In this case, signals can propagate from one direction to the other in the passageway, allowing coverage of the entire passageway. However, as previously mentioned, since metasurfaces measuring 1.2 m2 or more are installed obliquely against the walls, a significant portion of the passageway becomes unusable, potentially resulting in a disadvantage in space utilization.

[0149] FIGS. 16A and 16B illustrate another example of installing a metasurface according to an embodiment of the present disclosure. FIG. 16A illustrates an installation location of a metasurface (1630) in a space (1660), and FIG. 16B illustrates a signal transmission path according to an installation as in FIG. 16A. Referring to FIG. 16A, the metasurface (1630) may be installed on an outer wall of one of the passages, near the boundary where two passages meet. Specifically, the metasurface (1630) may be installed such that one edge of the metasurface (1630) contacts the boundary of the two passages and is in close contact with the outer wall of one of the passages. In this case, it is difficult for a signal to propagate from one of the two directions of the passage to the other. That is, if the metasurface is placed in close contact with the wall as in FIG. 16A to resolve the space inefficiency caused by an installation as in FIG. 15A, problems with signal transmission may occur.

[0150] As described above, although an arrangement such as that in FIG. 15a is ideal in that it can cover the entire space using a single metasurface (1530), it presents difficulties in terms of space utilization. On the other hand, an arrangement such as that in FIG. 16a makes it nearly impossible to use the metasurface / RIS because the effective area of ​​the metasurface / RIS does not cover the entire space, and thus the reflected beam does not reach the receiver. Therefore, the present disclosure proposes using multiple metasurfaces. The arrangement of metasurfaces according to one embodiment is as follows in FIGS. 17a and 17b.

[0151] FIGS. 17A and 17B illustrate another example of installing a metasurface according to an embodiment of the present disclosure. FIG. 17A illustrates the installation locations of metasurfaces (1730-1 and 1730-2) in a space (1760), and FIG. 17B illustrates a signal transmission path according to the installation as in FIG. 17A. Referring to FIG. 17A, each of the metasurfaces (1730-1 and 1730-2) may be installed on the outer wall of each of the passages in a space where two passages meet. Specifically, the metasurfaces (1730-1 and 1730-2) can be installed such that one edge of the first metasurface (1730-1) contacts the boundary of the two passages and adheres to the outer wall of the first passage, and one edge of the second metasurface (1730-2) contacts the boundary of the two passages and adheres to the outer wall of the second passage.

[0152] In the installation example of the metasurfaces (1730-1 and 1730-2) described with reference to FIGS. 17A and 17B, the metasurfaces (1730-1 and 1730-2) contact the boundary where two passages are connected. However, according to another embodiment, at least one of the metasurfaces (1730-1 and 1730-2) may be installed so as to be spaced apart from the boundary where two passages are connected by a certain distance. At this time, the distance of separation may vary depending on the width of the passages. That is, the metasurfaces (1730-1 and 1730-2) are installed on the outer walls of the two passages, respectively, and may be spaced apart from each other within a range where a quantum LOS path is secured.

[0153] According to the arrangement of the metasurfaces according to the above-described embodiment, it can be seen that one of the metasurfaces (1730-1 and 1730-2) operates as a feeder for the other metasurface. In addition, since the two metasurfaces are colocated, the loss part from the perspective of the reflective array must be considered. In particular, since the larger the size of the metasurface, the smaller the half power beam width (HPBW), if sufficient separation is not secured between the two metasurfaces, a very serious problem may occur in terms of illumination loss. Accordingly, the present disclosure proposes various embodiments for controlling a signal when at least one of a plurality of metasurfaces operates as a feeder, as follows.

[0154] In order to propose a method of controlling a signal, the experimental results for two metasurfaces are first examined as follows. FIGS. 18A and 18B illustrate the experimental results for metasurfaces arranged according to an embodiment of the present disclosure. FIG. 18A shows the energy pattern of a signal incident on a metasurface operating as a feeder (hereinafter, referred to as the first metasurface) when a single-beam is formed, and FIG. 18B shows the energy pattern of a signal incident on a metasurface operating as a reflector (hereinafter, referred to as the second metasurface) when a multi-beam is formed on the first metasurface. Referring to FIGS. 18A and 18B, when the first metasurface forms a single-beam, it can be confirmed that the HPBW is relatively very small, and the 6dB beamwidth is also very small. On the other hand, when the first metasurface forms a multi-beam, it can be confirmed that the 3dB / 6dB bandwidth is relatively large. However, when forming a multi-beam, multiple peak points occur, but as can be seen from the following experimental results, this does not pose a significant problem in the final signal transmission to the receiver.

[0155] FIGS. 19A and 19B illustrate examples of the shapes of beams formed from metasurfaces arranged according to one embodiment of the present disclosure. FIG. 19A illustrates a case where a single beam is formed from a first metasurface operating as a feeder, and FIG. 19B illustrates a case where a multi-beam is formed from the first metasurface, showing the beam pattern of a signal generated on a second metasurface operating as a reflector. Referring to FIGS. 19A and 19B, it can be confirmed that a sharper beam is formed when a multi-beam is formed. The directionality and EIRP (effective isotropically radiated power) of the beam pattern of the signal generated on the second metasurface are as follows.

[0156] FIGS. 20A and 20B illustrate experimental results for the directionality of beams formed from metasurfaces arranged according to an embodiment of the present disclosure, and FIGS. 21A and 21B illustrate experimental results for the EIRP of beams formed from metasurfaces arranged according to an embodiment of the present disclosure. Referring to FIGS. 20A, 20B, 21A, and 21B, it can be seen that when the first metasurface forms a single-beam and a multi-beam, differences occur not only in the shape of the beam but also in the directionality and EIRP. Specifically, when the multi-beam is incident on the second metasurface, it can be seen that about 9 dB more gain occurs in terms of directionality and about 25 dB more gain occurs in terms of EIRP. Here, the total energy of the single-beam and the multi-beam is the same.

[0157] As described above, according to the arrangement of two metasurfaces attached to the walls of each passage at the boundary of the passages, one metasurface acts as a feeder and the other metasurface acts as a reflector. When the first metasurface as a feeder forms a single beam and the second metasurface as a reflector reflects the single beam, the illumination loss increases, which may cause serious performance degradation in terms of not only the shape of the reflected beam but also the directionality and EIRP. However, when the first metasurface as a feeder forms a multi-beam and the second metasurface as a reflector reflects the multi-beam, the illumination loss decreases, and the effectiveness of using two metasurfaces may be achieved.

[0158] According to various embodiments of the present disclosure, a system transmits a signal using a first metasurface operating as a feeder and a second metasurface operating as a reflector, wherein the first metasurface forms a plurality of beams, i.e., a multi-beam, based on a signal from the transmitter. Multi-beam formation using the metasurface can be performed in various ways. Multi-beam formation techniques applicable to the system according to embodiments of the present disclosure are as follows.

[0159] First, the unit cells of the metasurface can be divided into multiple groups, and each group can be designed to reflect beams in different directions. In this case, multiple beams can be formed simultaneously using the metasurface or RIS, which can be useful for efficient communication with multiple devices. For example, to form two or three beams simultaneously, the metasurface is divided into two or three groups, and appropriate phase values ​​are applied to the unit cells within each group. The antenna elements of the two or three groups are then combined. The generated multiple beams point in different directions. In other words, the technology steers the beams by dividing the aperture of a single metasurface into multiple angular sectors.

[0160] Second, as a technology linked to polarization, if polarized isolation of the metasurface unit cell is secured, beams with different polarizations belonging to a dual polarized incident beam can be individually steered. However, if the incident beam is a single polarization beam, only one beam can be reflected. In other words, in the case of the technology, only a single beam per single polarization is possible, and at most two beams can be generated.

[0161] Third, multi-beam steering can be achieved by utilizing the chessboard metasurface principle, which is an evolution of coding metasurfaces. The chessboard metasurface, or coding sequence, is based on the principle that when unit cells with 0-degree phase shift and 180-degree phase shift are alternately arranged, the radio waves reflected from the unit cells cancel each other out, creating a new reflected beam. Using this technology, it is possible to generate various multi-beams using various chessboards. Therefore, multiple beams, such as two, four, or six, can be formed.

[0162] Fourth, multi-beam formation can be achieved based on multiple scatterings with non-equiphase fronts. This technique relies on the assumption that scattered beams have independent and identical distributions (iid), enabling complex weighted summation. A 180-degree phase shift can be added to the phase of a specific unit cell so that the reflected waves from that unit cell cancel each other out and are reflected back. The scattering-based multi-beam formation technique is described as follows.

[0163] FIG. 22 illustrates an example of beam forming using a non-uniform phase front in a metasurface according to one embodiment of the present disclosure. Referring to FIG. 22, a metasurface (2260) includes a plurality of unit cells (2250). According to one embodiment, each of the plurality of unit cells (2250) may include at least one of a reflective patch for reflecting a signal, at least one line to which a control signal for setting a phase shift value is applied, and a switch controlled according to the control signal. The metasurface (2260) according to various embodiments may generate a non-uniform phase front rather than a uniform phase front according to the phase pattern of the unit cells (2250), and may form at least one beam based on the non-uniform phase front. Due to the non-uniform phase front, a beam scattering phenomenon may occur, and a plurality of beams may be formed. At this time, even if an incident beam is single-polarized, a plurality of beams may be formed. The phenomenon of forming a plurality of beams may be explained as follows.

[0164] For example, when scattered beams are formed in two directions, the weighted sum of phasing vectors for the two directions can be expressed as follows [Mathematical Formula 1].

[0165]

[0166] In [Equation 1], is the weighted sum of phase vectors, is the phase vector for the first direction, denotes the phase vector for the second direction.

[0167] At this time, the complex weight sum set in the nth unit cell is as follows [Mathematical Formula 2].

[0168]

[0169] In [Equation 2], is the complex weighted sum set in the nth unit cell, is the phase constant for the first direction, denotes the phase constant for the second direction.

[0170] The amplitude term and phase term of the complex weight sum set in the nth unit cell can be expressed as in [Mathematical Formula 3] below.

[0171]

[0172] In [Equation 3], is the size value set for the nth unit cell, is the phase constant for the first direction, is the phase constant for the second direction, means the phase value set in the nth unit cell.

[0173] Here, the magnitude term is determined based on the coding sequence principle to implement a non-uniform phase front, and may be referred to as a 'bit term'. A negative term may be expressed as a coding sequence of 0, i.e., a phase shift of 0 degrees, and a positive term may be expressed as a coding sequence of 1, i.e., a phase shift of 180 degrees. The coding sequences set according to the negative and positive terms are added to the phase term, thereby implementing a non-uniform phase front. Due to the non-uniform phase front, interference (e.g., cancellation and reinforcement) may occur between beams, and as a result, multi-beams may be generated.

[0174] The operation of forming the two beams described above can be generalized as follows. A scattered beam pattern including k beams is formed, and the complex weighted sum for the nth unit cell of the metasurface can be expressed as follows [Mathematical Formula 4].

[0175]

[0176] In [Equation 4], is the complex weighted sum set in the nth unit cell, , , … , is the phase constant of each of the k beams, is half the wavelength of the signal, is the index of the unit cell, refers to the wavelength of the signal.

[0177] cast as, cast If substituted, the weighted sum for each unit cell can be organized as shown in [Mathematical Formula 5] below.

[0178]

[0179] In [Equation 5], is the complex weighted sum set in the nth unit cell, , , … , is the phase constant of each of the k beams, represents the index of the unit cell.

[0180] If we divide the complex weight sum set in the nth unit cell into an amplitude term and a phase term, the amplitude term and the phase term are as follows [Mathematical Formula 6].

[0181]

[0182] In [Equation 6], is the size value set for the nth unit cell, is the complex weighted sum set in the nth unit cell, means the phase value set in the nth unit cell.

[0183] When [Equation 6] is rearranged for the case of two beams, i.e., k=2, the following [Equation 7] and [Equation 8] are obtained.

[0184]

[0185] In [Equation 6], is the size value set for the nth unit cell, and denotes the phase constant for each of the two beams.

[0186]

[0187] In [Equation 8], is the phase value set in the nth unit cell, and denotes the phase constant for each of the two beams.

[0188] The weighted sum of the phase vectors determined according to [Mathematical Formula 8] is applied to each unit cell together with a code sequence entry (e.g., 0 or 1). The code sequence entry is determined based on a magnitude value determined as in [Mathematical Formula 7]. For example, the code sequence entry can be determined as 0 if the magnitude value is positive, and as 1 if the magnitude value is negative. That is, the final phase vector, i.e., the multi-beam phase vector, can be determined by adding the weighted sum of the phase vectors and the code sequence. Here, beam scattering occurs by the addition of the code sequence. Therefore, the code sequence may be referred to as a code vector, a scattering code, a scattering sequence, a scattering factor, a scattering vector, or other terms having an equivalent technical meaning thereto. Additionally, the weighted sum of phase vectors may be referred to as a 'weighted summed phase vector', a 'weighted summed phase pattern', a 'combined phase pattern' or other terms having equivalent technical meaning.

[0189] Any one of the various multi-beam forming techniques described above may be adopted for the embodiments described below. As described above, the signal quality of multi-beam forming is expected to be superior to that of single-beam forming. Specifically, when a single beam is formed from a metasurface operating as a feeder, the EIRP is expected to be approximately 12 dBm, when multi-beams are formed based on a subarray method, the EIRP is expected to be approximately 29 dBm, and when multi-beams are formed based on a scattering-beam method, the EIRP is expected to be approximately 39 dBm.

[0190] FIG. 23 illustrates an example of a structure for performing communication using RIS according to one embodiment of the present disclosure. FIG. 23 illustrates the structure of a system for performing communication using metasurfaces installed in a space in the form of a curved passage.

[0191] Referring to FIG. 23, the system includes a first device (2310), a second device (2320), RISs (2330-1, 2330-2), and a RIS controller (2380).

[0192] A first device (2310) transmits a signal to a second device (2320). The signal transmitted from the first device (2310) passes through a space (2360) to reach the second device (2320), and for this purpose, the signal is reflected by RISs (2330-1, 2330-2). Each of the RISs (2330-1, 2330-2) includes a metasurface including a plurality of unit cells, wherein the states (e.g., phase and magnitude) of each of the unit cells can be controlled by a RIS controller (2380). In the present disclosure, a set and / or combination of states of the unit cells included in one RIS or metasurface is referred to as a 'state pattern'. That is, one metasurface can have one state pattern at one point in time.

[0193] The first device (2310) can transmit a control signal to the RIS controller (2380) to control the RISs (2330-1, 2330-2). The control signal can indicate at least one of possible candidate states of the RISs (2330-1, 2330-2). Here, the possible candidate states of the RISs (2330-1, 2330-2) include a plurality of sets of candidate states for each of the directions of a signal passing through the space (2360) (e.g., a first direction from the first device (2310) to the second device (2320), a second direction from the second device (2320) to the first device (2310), and each set of candidate states includes states for reflecting a signal in different directions. One candidate state includes state patterns for each of the two RISs (2330-1, 2330-2). At this time, according to various embodiments, among the state patterns included in the candidate state, the state pattern for the RIS operating as a feeder causes the RIS to form a multi-beam, and the state pattern for the RIS operating as a reflector causes the incident multi-beam to be reflected into a single beam.

[0194] The first device (2310) can control the directionality of a signal passing through the space (2360) by transmitting a control signal to the RIS controller (2380) as needed. The first device (2310) can control the signal to be transmitted in multiple directions simultaneously or sequentially, or can control the signal to be transmitted in a specific desired direction.

[0195] In the example structure described with reference to FIG. 23, the first device (2310) controls two RISs (2330-1, 2330-2). According to various embodiments, the first device (2310) may further control at least one other RIS in addition to the RISs (2330-1, 2330-2). That is, the metasurfaces (2330-1, 2330-2) illustrated in FIG. 23 may be understood as part of the metasurfaces controlled by the first device (2310).

[0196] The operations using RISs according to the various embodiments described above can be used in various devices. For example, a base station, UE, vehicle, roadside unit (RSU), relay station, RIS, etc. of a wireless communication system can transmit signals using RISs according to the various embodiments described above. That is, the transmission operations using RISs according to the various embodiments can be used for at least one of downlink, uplink, or sidelink.

[0197] FIG. 24 illustrates an example of a procedure for performing an initial connection using RIS according to one embodiment of the present disclosure. FIG. 24 illustrates an operation method of a device transmitting a signal (e.g., the first device (2310) of FIG. 23).

[0198] Referring to FIG. 24, in step S2401, the device generates at least one signal. Here, the signal includes information to be transmitted to another device. The signal may be generated by different operations depending on the type of signal. For example, the device may generate a signal for synchronization, a signal including system information, or a signal including data. For example, when generating a signal for synchronization, the device may generate at least one of synchronization signals including at least one sequence determined based on a cell identifier (ID) and a broadcast signal including system information. When generating a signal including system information or data, the device may perform at least one of channel coding, scrambling, rate matching, and constellation mapping.

[0199] In step S2403, the device identifies at least one desired direction. The desired direction may be determined differently depending on the type of generated signal. For example, the desired direction may be determined according to a predefined pattern, determined by scheduling, or determined according to a beam management procedure. In one embodiment, the device may identify the desired directions based on measurement results for other signals (e.g., a reference signal, a synchronization signal), or based on feedback from a counterpart device.

[0200] In step S2405, the device transmits a signal in at least one direction identified using the RISs. That is, the device forms beams directed toward the directions identified in step S2403 using the at least one signal generated in step S2401. In other words, the device can transmit a signal toward RISs installed in a space having a limited structure (e.g., a space in the form of a curved passage) and control the RISs to reflect the signal in at least one target direction. That is, the device controls the unit cells included in the RISs to states corresponding to the identified directions. According to various embodiments, the device can perform multi-beam beamforming using the scattering phenomenon of the metasurface.

[0201] FIG. 25 illustrates an example of a procedure for transmitting a signal using RIS according to one embodiment of the present disclosure. FIG. 25 illustrates an operation method of a device for transmitting a signal (e.g., the first device (2310) of FIG. 23).

[0202] Referring to FIG. 25, in step S2501, the device generates a control message for RISs. According to various embodiments of the present disclosure, the device generates a control message for controlling a first RIS and a second RIS, which are installed in a space in the form of a curved passage as a connection of two passages. Here, the first RIS is used to reflect a signal transmitted from the device, and the second RIS is used to reflect a signal reflected by the first RIS toward another device. To this end, according to one embodiment, the device generates a control message for controlling the first RIS to form a multi-beam, and for controlling the second RIS to form a single beam based on the multi-beam.

[0203] In step S2503, the device transmits a control message to the RIS controller. The device transmits the control message generated in step S2501 to the RIS controller. The control message may include values ​​of control signals to be applied to the first RIS and the second RIS, or may include identification information for the control signals. In addition, the control message may indicate at least one direction in which the signal is to be transmitted. In one embodiment, the control message may indicate sweeping of possible candidate directions.

[0204] In step S2505, the device transmits a signal toward the RISs. That is, after transmitting the control message or together with the transmission of the control message, the device transmits a signal to be transmitted to another device toward the RISs. At this time, the device transmits the signal toward the first RIS. Accordingly, the signal reaching the first RIS is beamformed into a multi-beam, and is beamformed and steered into a single beam by the second RIS, thereby reaching the other device.

[0205] According to the above-described embodiments, the device can transmit a signal to another device through a space in the form of a curved passage using RISs. To this end, according to various embodiments, the RIS that reflects the signal first among the RISs forms a multi-beam. There are various techniques for forming the multi-beam, and at least one of the various techniques can be applied to the system according to the embodiments of the present disclosure. As one of the various techniques, a multi-beam beamforming technique using a scattering phenomenon on a metasurface can be applied. The operation of the RIS controller for performing operations according to the multi-beam beamforming technique using a scattering phenomenon is as follows in FIG. 26.

[0206] FIG. 26 illustrates an example of a procedure for performing multi-beam beamforming using RIS according to one embodiment of the present disclosure. FIG. 26 illustrates an operation method of a device for transmitting a signal (e.g., the RIS controller (2380) of FIG. 23).

[0207] Referring to FIG. 26, in step S2601, the device identifies target directions. Here, the target directions include two or more directions. The two or more directions may be independent of each other. For example, the two or more directions may include predefined directions.

[0208] In step S2603, the device determines a phase pattern for each direction. The phase pattern refers to a set of phase values ​​for reflection of a signal generated from unit cells included in the metasurface. In other words, the device determines phase values ​​to be applied to the unit cells included in the metasurface. In other words, the device can calculate the analog phase required for the unit cells for beamforming in each direction. For example, phase patterns for each direction may be predefined, and the device can check the phase patterns corresponding to each of the selected directions from a predefined mapping table. As another example, an equation for a phase pattern based on angle values ​​indicating a direction may be defined, and the device can determine the phase patterns using the equation.

[0209] At step S2605, the device determines a combined phase pattern. The combined phase pattern is a weighted sum of phase patterns for the intended directions and includes the same number of phase values ​​as the phase patterns for each direction. Specifically, the device can combine the phase patterns by checking the weights for each direction and summing the products of the weights for each direction and the phase values ​​for each beam for each unit cell. If the weights for the directions are the same, the weighted sum can be understood as averaging.

[0210] In step S2607, the device determines a scattering vector. The scattering vector can be understood as a phase sequence applied to the metasurface to cause beam scattering. To this end, the device can determine a magnitude vector based on phase patterns for intended directions, and determine the scattering vector based on magnitude values ​​included in the magnitude vector. In one embodiment, the device can determine the scattering vector based on a result value of a cosine operation on a weighted sum of phase patterns for each direction. For example, some of the weights for the weighted sum may be negative. Additionally, the sum of the absolute values ​​of the weights for the weighted sum may be 1. As a specific example, when two directions are intended, the weights may be 1 / 2 and -1 / 2. In this case, the value of each element included in the scattering vector may be determined depending on whether the result value of the cosine operation is negative or positive. Here, each element of the scattering vector may have a value of 0 degrees or 260 degrees.

[0211] In step S2609, the device forms scattering beams based on the weighted sum phase pattern and the scattering vector. Specifically, the device can transmit a source signal in multiple directions by applying the weighted sum phase pattern and the scattering vector to the unit cells. In other words, the device determines a phase pattern for multi-beam beamforming applied to the metasurface by summing the weighted sum phase pattern and the scattering vector for each unit cell, and controls the unit cells by outputting a control signal corresponding to the phase pattern for multi-beam beamforming. Then, the device radiates the source signal toward the metasurface so that the metasurface reflects the source signal. Accordingly, a beam scattering phenomenon can occur at the metasurface.

[0212] The proposed methods described above can be implemented independently, but they can also be implemented as a combination (or merge) of some of the proposed methods. Rules can be defined so that the base station notifies the terminal of the applicability of the proposed methods (or information about the rules of the proposed methods) through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0213] The present disclosure may be embodied in other specific forms without departing from the technical ideas and essential features described herein. Therefore, the above detailed description should not be construed as limiting in all respects but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are intended to be included within the scope of the present disclosure. Furthermore, claims that are not explicitly cited in the claims may be combined to form an embodiment or incorporated into a new claim through a post-filing amendment.

[0214] Embodiments of the present disclosure can be applied to various wireless access systems. Examples of various wireless access systems include the 3rd Generation Partnership Project (3GPP) or 3GPP2 systems.

[0215] The embodiments of the present disclosure can be applied not only to the various wireless access systems described above, but also to all technical fields that utilize these various wireless access systems. Furthermore, the proposed method can also be applied to mmWave and THz communication systems utilizing ultra-high frequency bands.

[0216] Additionally, embodiments of the present disclosure can be applied to various applications such as autonomous vehicles and drones.

Claims

1. In a method of operating a first device in a wireless communication system, generating at least one sequence for a synchronization signal; generating the synchronization signal based on at least one sequence; A step of generating a broadcast signal including system information; A step of determining directions for transmitting the above synchronization signal and the above broadcast signal; and A step of transmitting the synchronization signal and the broadcast signal in the above directions, A method in which the above-mentioned synchronization signal and the above-mentioned broadcast signal are transmitted from the first device located on one side of the bent passage to the second device located on the other side of the bent passage by being reflected by the first RIS (reconfigurable intelligent surface) installed on the wall of the first passage and the second RIS installed on the wall of the second passage in a bent passage-shaped space in which the first passage and the second passage are connected.

2. In claim 1, A method further comprising the step of transmitting a control message for controlling state patterns of the first RIS and the second RIS to a controller controlling the first RIS and the second RIS.

3. In claim 2, A method in which the control message includes at least one of values ​​of control signals to be applied to the first RIS and the second RIS, identification information for the control signals, the synchronization signal, and at least one direction in which the broadcast signal is to be transmitted.

4. In claim 3, A method wherein at least one of the directions comprises sweeping of possible candidate directions.

5. In claim 1, The above first RIS is installed on the outer wall of the first passage, The above second RIS is installed on the outer wall of the second passage.

6. In claim 5, The above first RIS and the above second RIS are installed so that a line of sight (LOS) path is secured.

7. In claim 1, The above first RIS is controlled to reflect the incident signal into a multi-beam, The above second RIS is a method controlled to reflect the incident multi-beam into a single beam.

8. In claim 7, The above first RIS is a method for forming scattered beams directed toward each of the directions by applying a scattering vector for beam scattering and a combination of phase patterns for each of the directions of beams included in the multi-beam.

9. In claim 8, A method for forming the multi-beam by applying the combined phase pattern and the scattering vector, which are determined based on the phase patterns for the directions, to the unit cells of the first RIS.

10. In claim 9, A method in which the above combined phase pattern is determined by weighted summing of phase values ​​included in the above phase patterns for each unit cell.

11. In a first device in a wireless communication system, Transmitter and receiver; and comprising a processor connected to the above transceiver, The above processor, Generate at least one sequence for the synchronization signal, Generating the synchronization signal based on at least one sequence, Generate a broadcast signal containing system information, Determine the directions for transmitting the above synchronization signal and the above broadcast signal, Control to transmit the synchronization signal and the broadcast signal in the above directions, A first device in which the synchronization signal and the broadcast signal are reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of the first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage connecting a first passage and a second passage, thereby transmitting the signal from the first device located on one side of the curved passage toward the second device located on the other side of the curved passage.

12. In communication devices, At least one processor; At least one computer memory connected to said at least one processor and storing instructions that direct operations when executed by said at least one processor, The above actions are, generating at least one sequence for a synchronization signal; generating the synchronization signal based on at least one sequence; A step of generating a broadcast signal including system information; A step of determining directions for transmitting the above synchronization signal and the above broadcast signal; and A step of transmitting the synchronization signal and the broadcast signal in the above directions, A communication device in which the above-mentioned synchronization signal and the above-mentioned broadcast signal are reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of the first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage connecting a first passage and a second passage, thereby transmitting the signal from the communication device located on one side of the curved passage toward another communication device located on the other side of the curved passage.

13. In a non-transitory computer-readable medium storing at least one instruction, comprising at least one instruction executable by the processor, At least one of the above commands causes the device to: Generate at least one sequence for the synchronization signal, Generating the synchronization signal based on at least one sequence, Generate a broadcast signal containing system information, Determine the directions for transmitting the above synchronization signal and the above broadcast signal, Control to transmit the synchronization signal and the broadcast signal in the above directions, A non-transitory computer-readable medium in which the above-mentioned synchronization signal and the above-mentioned broadcast signal are reflected by a first RIS (reconfigurable intelligent surface) installed on a wall surface of the first passage and a second RIS installed on a wall surface of the second passage in a space in the form of a curved passage connecting a first passage and a second passage, thereby transmitting the signal from the device located on one side of the curved passage to another device located on the other side of the curved passage.

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