Apparatus and method for transmitting and receiving signal using reconfigurable intelligent surface in wireless communication system

Abstract

The present disclosure is for efficiently transmitting and receiving a signal by using a reconfigurable intelligent surface (RIS) in a wireless communication system, and an operation method of a terminal may comprise the steps of: receiving a first reference signal for measuring a first channel from a base station; transmitting a first measurement report message to the base station on the basis of the first reference signal; receiving information on a signal to interference and noise ratio (SINR) value from the base station; requesting the base station to change a message ratio on the basis of the SINR value; and receiving a data signal from the base station.

Description

Device and method for transmitting and receiving signals using a reconfigurable intelligent surface in a wireless communication system

[0001] The following description relates to a wireless communication system, and to a device and method for transmitting and receiving rate splitting multiple access (RSMA) signals using a reconfigurable intelligence surface (RIS) 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 multiple 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 solutions.

[0004] The present disclosure may provide a device and method for transmitting and receiving a signal using a reconfigurable intelligence surface (RIS) in a wireless communication system.

[0005] The present disclosure may provide a device and method for transmitting and receiving a rate splitting multiple access (RSMA) signal in a wireless communication system.

[0006] The present disclosure can provide a device and method for transmitting and receiving RSMA signals using a 2-layer HRS (hierarchical rate splitting) structure in a wireless communication system.

[0007] The present disclosure may provide a device and method for performing RIS and RRC (radio resource control) connection in a wireless communication system.

[0008] The present disclosure may provide a device and method for changing a message rate based on SINR in a wireless communication system.

[0009] The present disclosure may provide a device and method for classifying terminals based on distribution of channel gain in a wireless communication system.

[0010] The present disclosure can provide a device and method for detecting a change in a channel environment in a wireless communication system and optimizing a beamformer, RIS reflection pattern, and message rate.

[0011] The present disclosure may provide a device and method for optimizing beamformers, RIS reflection patterns, and message rates for each group in a wireless communication system.

[0012] The present disclosure may provide a device and method for performing optimization using a weighted minimum mean square error (WMMSE) technique in a wireless communication system.

[0013] The present disclosure can provide a device and method for transmitting an SINR value using an SINR code in a wireless communication system.

[0014] The present disclosure relates to a device and method for transmitting a plurality of transport blocks (TBs) as a single unit in a wireless communication system.

[0015] 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.

[0016] As an example of the present disclosure, a method of operating a terminal in a wireless communication system includes the steps of: receiving a first reference signal for measuring a first channel from a base station; transmitting a first measurement report message to the base station based on the first reference signal; receiving information regarding a signal to interference and noise ratio (SINR) value from the base station; requesting the base station to change a message ratio based on the SINR value; and receiving a data signal from the base station, wherein the terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal, or a second group using a direct channel between the terminal and the base station, based on the first measurement report message, and the data signal may include a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and private messages decoded by each of the terminals.

[0017] As an example of the present disclosure, a method of operating a base station in a wireless communication system comprises the steps of: transmitting a first reference signal for measuring a first channel to a terminal; receiving a first measurement report message based on the first reference signal from the terminal; transmitting information on a signal to interference and noise ratio (SINR) value to the terminal; receiving a request for changing a message ratio based on the SINR value from the terminal; changing the message ratio based on the request for changing the message ratio; and transmitting a data signal to the terminal, wherein the terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, and the data signal comprises a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and terminals It may contain personal messages that are decoded by each person.

[0018] As an example of the present disclosure, in a wireless communication system, a terminal includes a transceiver and a processor connected to the transceiver, wherein the processor receives a first reference signal for measuring a first channel from a base station, transmits a first measurement report message to the base station based on the first reference signal, receives information about a signal to interference and noise ratio (SINR) value from the base station, performs a request for changing a message ratio based on the SINR value to the base station, and receives a data signal from the base station, wherein the terminal is included in one of a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal, or a second group using a direct channel between the terminal and the base station, and the data signal includes a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and a third shared message decoded by terminals belonging to each of the terminals. It may contain private messages that are decoded by.

[0019] As an example of the present disclosure, in a wireless communication system, a base station includes a transceiver and a processor connected to the transceiver, wherein the processor transmits a first reference signal for measuring a first channel to a terminal, receives a first measurement report message based on the first reference signal from the terminal, transmits information about a signal to interference and noise ratio (SINR) value to the terminal, receives a request for changing a message ratio based on the SINR value from the terminal, changes the message ratio based on the request for changing the message ratio, and controls transmission of a data signal to the terminal, wherein the terminal is included in one of a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, and the data signal includes a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, and a second shared message decoded by terminals belonging to the second group. It may include a third shared message decoded by the terminals and private messages decoded by each of the terminals.

[0020] As an example of the present disclosure, a communication device comprises at least one processor, and at least one computer memory connected to the at least one processor, and storing instructions that direct operations when executed by the at least one processor, the operations including: receiving a first reference signal for measuring a first channel from a base station, transmitting a first measurement report message to the base station based on the first reference signal, receiving information about a signal to interference and noise ratio (SINR) value from the base station, requesting the base station to change a message ratio based on the SINR value, and receiving a data signal from the base station, wherein the communication device is included in one of a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the communication device based on the first measurement report message, or a second group using a direct channel between the communication device and the base station, and the data signal is a first shared message decoded by communication devices belonging to the first group and the second group, and a first shared message decoded by communication devices belonging to the first group. It may include a second shared message, a third shared message decoded by the communication devices belonging to the second group, and private messages decoded by each of the communication devices.

[0021] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction, the at least one instruction being executable by a processor, the at least one instruction controlling a device to receive a first reference signal for measuring a first channel from a base station, transmit a first measurement report message to the base station based on the first reference signal, receive information about a signal to interference and noise ratio (SINR) value from the base station, request the base station to change a message ratio based on the SINR value, and receive a data signal from the base station, wherein the device is included in one of a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the device, or a second group using a direct channel between the device and the base station, based on the first measurement report message, and wherein the data signal comprises a first shared message decoded by devices belonging to the first group and the second group, It may include a second shared message decoded by devices belonging to the first group, a third shared message decoded by devices belonging to the second group, and private messages decoded by each of the devices.

[0022] 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.

[0023] The following effects may be achieved by embodiments based on the present disclosure.

[0024] According to the present disclosure, a wireless communication system can efficiently transmit and receive signals using a reconfigurable intelligence surface (RIS).

[0025] According to the present disclosure, RSMA signals can be efficiently transmitted and received using a 2-layer HRS (hierarchical rate splitting) structure.

[0026] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects that are 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 that result from implementing the configuration described in the present disclosure can also be derived by those skilled in the art from the embodiments of the present disclosure.

[0027] The accompanying drawings are intended to aid in understanding the present disclosure and, together with detailed descriptions, may provide embodiments of the present disclosure. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0028] FIG. 1 is a diagram illustrating an example of a communication system applicable to the present disclosure.

[0029] FIG. 2 is a drawing showing an example of a wireless device applicable to the present disclosure.

[0030] FIG. 3 is a diagram showing another example of a wireless device applicable to the present disclosure.

[0031] FIG. 4 is a drawing showing an example of a mobile device applicable to the present disclosure.

[0032] FIG. 5 is a drawing showing an example of a vehicle or autonomous vehicle applicable to the present disclosure.

[0033] Figure 6 is a diagram showing an example of AI (Artificial Intelligence) applicable to the present disclosure.

[0034] FIG. 7 is a diagram illustrating a method for processing a transmission signal applicable to the present disclosure.

[0035] FIG. 8 is a diagram showing an example of a communication structure that can be provided in a 6G system applicable to the present disclosure.

[0036] Figure 9 is a diagram showing an electromagnetic spectrum applicable to the present disclosure.

[0037] Fig. 10 is a diagram showing a THz communication method applicable to the present disclosure.

[0038] FIG. 11 is a diagram illustrating a wireless channel environment according to one embodiment of the present disclosure.

[0039] FIG. 12 is a diagram illustrating an intelligent wireless environment according to one embodiment of the present disclosure.

[0040] FIG. 13 is a diagram illustrating a communication environment of an RSMA (rate splitting multiple access) system according to one embodiment of the present disclosure.

[0041] FIG. 14 is a diagram showing the structure of a transmitter and receiver in an RSMA system according to one embodiment of the present disclosure.

[0042] FIG. 15 illustrates an example of the structure of 2-layer HRS (hierarchical rate splitting), which is an extension technology of RSMA, according to one embodiment of the present disclosure.

[0043] FIG. 16 illustrates an example of a procedure in which a base station controls RIS through an RRC (radio resource control) connection according to one embodiment of the present disclosure.

[0044] FIG. 17 illustrates an example of an environment in which a 2-layer HRS structure and RIS user grouping are combined according to one embodiment of the present disclosure.

[0045] FIG. 18 illustrates an example of a procedure for a terminal to receive an RSMA signal of a 2-layer HRS structure according to one embodiment of the present disclosure.

[0046] FIG. 19 illustrates an example of a procedure in which a base station transmits an RSMA signal of a 2-layer HRS structure according to one embodiment of the present disclosure.

[0047] FIG. 20 illustrates an example of signaling between a base station and a terminal for optimizing transmission and reception of RSMA signals based on variations in signal to interference and noise ratio (SINR) values ​​according to one embodiment of the present disclosure.

[0048] FIG. 21 illustrates an example of signaling between a base station, an RIS, and terminals for transmitting RSMA signals based on grouping, according to one embodiment of the present disclosure.

[0049] The following embodiments combine 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] Additionally, in 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).

[0055] 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.

[0056] 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.

[0057] Furthermore, the embodiments of the present disclosure may be applied to other wireless access systems and are not limited to the aforementioned systems. For example, they may be applicable to systems implemented after the 3GPP 5G NR system, and are not limited to a specific system.

[0058] 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.

[0059] 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.

[0060] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding 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.

[0061] 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).

[0062] In order to make the following description clear, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical idea of ​​the present invention is not limited thereto. LTE may refer to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 may be referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 may be referred to as LTE-A pro. 3GPP NR may refer to technology after TS 38.xxx Release 15. 3GPP 6G may refer to technology after TS Release 17 and / or Release 18. "xxx" refers to a standard document detail number. LTE / NR / 6G may be collectively referred to as a 3GPP system.

[0063] For background information, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to the present invention. For example, reference may be made to the 36.xxx and 38.xxx standard documents.

[0064] Communication system applicable to the present disclosure

[0065] 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.

[0066] 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.

[0067] FIG. 1 is a diagram illustrating an example of a communication system applied to the present disclosure.

[0068] 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.

[0069] 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).

[0070] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base stations (120), and base stations (120) / base stations (120). Here, the wireless communication / connection can be established through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and base station-to-base station communication (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and base station / wireless device, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, 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.

[0071] Communication system applicable to the present disclosure

[0072] FIG. 2 is a diagram illustrating an example of a wireless device applicable to the present disclosure.

[0073] 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.

[0074] 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.

[0075] 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 instructions 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] Wireless device structure applicable to the present disclosure

[0081] FIG. 3 is a diagram illustrating another example of a wireless device applicable to the present disclosure.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] Mobile devices to which the present disclosure applies

[0086] FIG. 4 is a drawing illustrating an example of a mobile device applied to the present disclosure.

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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).

[0091] Types of wireless devices to which the present disclosure applies

[0092] FIG. 5 is a drawing illustrating an example of a vehicle or autonomous vehicle to which the present disclosure applies.

[0093] 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.

[0094] 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.

[0095] 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).

[0096] 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.

[0097] 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.

[0098] 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).

[0099] 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.

[0100] 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).

[0101] 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.

[0102] 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).

[0103] 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 embodiments.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 6G communication system

[0109] 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.

[0110] Per device peak data rate1 TbpsE2E latency1 msMaximum spectral efficiency100 bps / HzMobility supportup to 1000 km / hrSatellite integrationFullyAIFullyAutonomous vehicleFullyXRFullyHaptic CommunicationFully

[0111] 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.

[0112] FIG. 8 is a diagram illustrating an example of a communication structure that can be provided in a 6G system applicable to the present disclosure.

[0113] Referring to Figure 8, 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.

[0114] Core implementation technology of 6G systems

[0115] - Artificial Intelligence (AI)

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] However, the application of DNN for transmission at the physical layer may have the following problems.

[0121] 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.

[0122] 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.

[0123] Below, we will look at machine learning in more detail.

[0124] 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.

[0125] 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.

[0126] Supervised learning uses labeled training data, while unsupervised learning may not have labeled training data. For example, in the case of supervised learning for data classification, the training data may be data in which each training data category is labeled. The labeled training data is input to a neural network, and the error can be calculated by comparing the output (categories) of the neural network with the training data labels. The calculated error is backpropagated through the neural network in the backward direction (i.e., from the output layer to the input layer), and the connection weights of each node in each layer of the neural network can be updated through backpropagation. The amount of change in the connection weights of each updated node can be determined by the learning rate. The neural network's calculation of the input data and the backpropagation of the error can constitute a learning cycle (epoch). The learning rate can be applied differently depending on the number of iterations of the neural network's learning cycle. For example, in the early stages of training a neural network, a high learning rate can be used to quickly allow the network to reach a certain level of performance, thereby improving efficiency. In the later stages of training, a low learning rate can be used to improve accuracy.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] THz (Terahertz) communication

[0131] 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.

[0132] 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.

[0133] 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.

[0134] Terahertz (THz) wireless communications

[0135] FIG. 10 is a diagram illustrating a THz communication method applicable to the present disclosure.

[0136] 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.

[0137] Specific embodiments of the present invention

[0138] In the following, we propose a method to configure a smart radio environment (SRE) by utilizing the characteristics of reconfigurable intelligent surface (RIS) and rate splitting multiple access (RSMA) techniques and to overcome the limitations of channel capacity due to free space path loss (FSPL), which is a characteristic of high-frequency channels such as mmWave / terahertz.

[0139] Current wireless communication technologies support multiple access technologies. Communication system performance can be affected by the type of multiple access technology. Multiple access technologies can be categorized into orthogonal and non-orthogonal. Various communications, such as LTE and 5G, adopt orthogonal frequency division multiple access (OFDMA), a type of orthogonal multiple access (OMA) technology. When a base station transmits the same message to multiple terminals, the multiple orthogonal access method can be inefficient. Therefore, RSMA technology is being researched to further improve communication efficiency. RSMA technology splits transmissions according to data purpose to efficiently utilize frequency.

[0140] RSMA technology can separate messages into a common message, which all users can decode, and a private message, which only specific users can decode. Users can decrypt the common message using a shared codebook. Conversely, private messages can only be decrypted by users with a specific codebook. Therefore, users can first decrypt the common message to obtain information relevant to them. Subsequently, they can use successive interference cancellation (SIC) to remove the common message and decrypt the private message. Therefore, users can decrypt the private message with interference from the common message removed through SIC, which provides the advantage of SIC.

[0141] RSMA technology's common and private messages can be combined in various ways depending on the user's environment. OMA technologies, such as OFMDA, require independent frequency band allocation for each user. In contrast, RSMA's common message is a message that all users can decrypt, allowing the simultaneous transmission of identical data in a shared format among multiple users. Therefore, when the same data needs to be transmitted to multiple users, cooperative transmission can be implemented among multiple users, thereby improving spectral efficiency.

[0142] Additionally, communication can be performed based on a new communication system, the Intelligent Wireless Environment. In this intelligent wireless environment, parameters related to RIS can be used as factors to control wireless channels, similar to a transmitter and receiver.

[0143] That is, factors for wireless channels using RIS can be added to optimize wireless communication transmission. This can overcome problems that are intractable in existing communication systems (e.g., channel reconfiguration, Shannon's channel capacity limit, etc.). However, in an intelligent wireless environment, additional channel measurements using RIS are required, and simultaneous consideration of RIS with the transmitter and receiver can lead to complex and challenging issues.

[0144] FIG. 11 is a diagram illustrating a wireless channel environment according to an embodiment of the present disclosure. Referring to FIG. 11, in a conventional communication system, the wireless channel environment (H) may be naturally fixed and in an uncontrollable random state. Accordingly, the transmitter (1110) and the receiver (1120) can adapt to the channel and find an optimized transmission and reception method. The transmitter (1110) and the receiver (1120) can be controlled to measure the channel state through a signal (e.g., a reference signal) and perform optimization based on the measured channel state. However, in environments with high signal loss, such as terahertz environments, where multipath application is difficult, and in non-line of sight (NLOS) environments, such as shaded areas, data transmission may be limited. For example, the following [Mathematical Equation 1] may represent Shannon's capacity limit.

[0145]

[0146] At this time, even if the transmission signal P in [Mathematical Formula 1] is increased by applying precoding and processing, there may be a limit to increasing the channel capacity if the size of the channel |H| is small.

[0147] In a fixed wireless channel environment, there may be limitations in increasing channel capacity based on [Mathematical Formula 1]. In this case, communication using RIS can secure multiple paths between the transmitter (1110) and the receiver (1120), and can increase the channel |H| described above. In other words, in an intelligent wireless environment, the wireless channel environment based on RIS can be an adjustable factor, and through this, the channel capacity can be increased.

[0148] FIG. 12 is a diagram illustrating an intelligent wireless environment according to an embodiment of the present disclosure. The intelligent environment technology may also be referred to as wireless 2.0. Referring to FIG. 12, in an intelligent wireless channel environment, the wireless channel |H| may be a factor for optimization. More specifically, in FIG. 11 described above, optimization may be performed at the transmitter (1110) and the receiver (1120) based on "max{f(Tx, Rx)}" as an end-point optimization, as described above. However, in FIG. 12, optimization may be performed at the transmitter (1210) and the receiver (1220) based on "max{f(Tx, Rx, H)}" as an end-point optimization. That is, in an intelligent wireless environment, the channel |H| may be used as a factor for optimization based on an intelligent reflector.

[0149] Figure 13 is a diagram illustrating a communication environment of an RSMA system according to one embodiment of the present disclosure. In wireless communication systems, RSMA technology can be used for multiple access. By utilizing RSMA technology, interference and resources between multiple users can be efficiently managed. As described above, a key feature of RSMA technology is to classify messages into common messages and private messages. Since common messages can be eliminated through a sequential interference cancellation technique, a terminal can decrypt the private messages after eliminating interference caused by the common messages. Therefore, when decrypting private messages, only interference from private messages of other terminals exists. In other words, the ratio of interference signals included in the common messages and private messages can be adjusted. Since RSMA technology is still in the research phase, standard guidelines for how to use frequency and time resources may not exist. However, RSMA technology can be studied in the same direction as how NOMA (non-orthogonal multiple access) technology uses frequencies. That is, all users can share frequency and time resources. As shown in Figure 13, k terminals can communicate based on RSMA technology.

[0150] FIG. 14 is a diagram illustrating a structure of a transmitter and receiver in an RSMA system according to an embodiment of the present disclosure. Referring to FIG. 14, a transmitter (1410) and a receiver (1420) in an RSMA system can transmit and receive wireless signals. In FIG. 14, the number of antennas can be changed depending on the antenna structures of the transmitter (1410) and the receiver (1420). The transmitter (1410) of FIG. 14 can represent a structure for transmitting messages to k users within a baseband. In a 1-layer RS ​​(rate split) structure, the transmitter (1410) can combine common messages of all users into one and transmit the remaining individual messages to each user. Each user's message , and each user's message is shared with a common message through the message distributor (1401). and private message can be distributed. The common messages of each user are combined into one common message through the common message combiner (1403). can be integrated. Each of the integrated common message and private message is transmitted through the encoder (1405). It can be encoded. After that, the encoded signal is precoded through a precoder (1407) and can be transmitted after undergoing radio processing (RF processing). That is, the transmission signal X obtained by processing K+1 messages by the transmitter (1410) can be expressed as in [Mathematical Formula 2].

[0151]

[0152] In [Equation 2], means the precoding coefficient of the common message, represents the precoding coefficient of a private message, and K represents the number of terminals. Precoding matrix The signal received by the kth user can be expressed as in [Mathematical Formula 3] below.

[0153]

[0154] In [Equation 3], refers to the channel of the kth user, stands for Gaussian Channel Noise.

[0155] The transmission rate of each user's common message and personal message can be expressed as in [Mathematical Formula 4] below.

[0156]

[0157]

[0158] In [Equation 4], represents the common message transmission rate received by the kth user, represents the personal message delivery rate received by the kth user, represents the variance of Gaussian channel noise.

[0159] In an RSMA system, the minimum transmission rate required for all users to decrypt a common message The following [Mathematical Formula 5] may need to be satisfied.

[0160]

[0161] The receiver (1420) of the kth user receives the signal , and first receive a common message can be decrypted through the decoder (1409). Common message is the common message of the kth user through the common message distributor (1413). can be obtained. In addition, the receiving unit (1420) receives the received signal Common message decrypted in After removing the common message through the sequential interference cancellation technique, the remaining private messages can be decrypted through the decoder (1411). The receiving unit (1420) decrypts the common message and private messages Each can generate a message for the kth user by combining them through a combiner (1415).

[0162] The present disclosure provides a method for a base station to proactively provide services to shadow areas using RIS in an intelligent wireless environment, thereby increasing communication services. In this case, the RIS may be replaced by a relay station or an integrated access and backhaul (IAB) node with limited functionality. Here, limited functionality means being implemented with low hardware capabilities or operating with some functions blocked depending on the operating mode. In other words, the RIS is not limited to a specific name, but can be generally referred to as a device that can provide a direct path and a different path to a receiving device by utilizing a reflective surface.

[0163] Additionally, the RIS can be implemented as a terminal with limited functionality, in which case it can establish an RRC connection with the base station. In this case, RIS configuration can be performed between the base station and the RIS through an RRC connection. The base station can control the RIS through the RRC connection and determine the optimal RIS reflection pattern through functions such as channel measurement or channel state information reporting of the terminal. In this case, channel measurement and channel state information reporting can be performed based on a reference signal (e.g., channel state information - reference signal, sounding reference signal, etc.).

[0164] At this time, the RIS reflection pattern may refer to phase change values ​​for controlling the elements of the RIS, and is not limited to a specific term. For example, the RIS reflection pattern may be referred to as a RIS phase pattern, a RIS control pattern, etc.

[0165] The base station can determine the RIS user group by calculating the variance based on the normalized channel gain value of the status of the terminals. For example, the base station can transmit a reference signal for multiple RIS reflection patterns to the terminals. At this time, the terminals can transmit a channel gain value corresponding to each of the multiple RIS reflection patterns to the base station. The base station can normalize the channel gain value and determine a variance value. At this time, the base station can classify the terminals into RIS user groups based on the variance value. The method of classifying the RIS user groups is not limited to a specific method. For example, regardless of the RIS reflection pattern, terminals having a channel gain above a certain threshold value can be classified into a direct user group, and the rest can be classified into a RIS user group. In this case, the direct user group refers to a group that uses a direct channel between the base station and the terminal, and the RIS user group refers to a group that uses a RIS channel including a channel between the base station and the RIS and a channel between the RIS and the terminal. In the following, the direct user group may be referred to as a non-RIS user group. That is, the RIS channel can refer to a channel existing in the path where a signal transmitted from a base station is reflected by the RIS and transmitted to a terminal. The base station can incorporate RSMA technology based on the classified user group. Therefore, the base station can actively determine the ratio of shared messages and private messages that satisfies the maximum sum rate and max-min fairness in a communication environment that changes in real time. That is, the base station can divide the user group into a direct user group and a RIS user group to utilize RIS in a communication environment with k multiple users, and can use a 2-layer HRS (hierarchical rate splitting) structure to incorporate RSMA technology.

[0166] Figure 15 illustrates an example of the structure of a 2-layer HRS, an extension technology of RSMA, according to one embodiment of the present disclosure. In Figure 15, it is assumed that there are four users, with the first and second users classified as Group 1, and the third and fourth users classified as Group 2.

[0167] Externally shared messages convey common information to all users, while internally shared messages convey common information to a limited number of users. Therefore, the two-layer HRS structure can be effectively utilized for resource management and optimization within specific user groups.

[0168] Specifically, the message splitter can split each message of four users and send it to the message combiner. For example, message W1 for user 1 can be sent to W1 through the message splitter. 1234 , W1 12 and W1 1 can be separated. At this time, message splitter W1 1234 is included in the external shared message, and W1 12 is included in the first group internal shared message, W1 1 can be classified as private messages. The message splitter performs the same operation on messages for users 2, 3, and 4 as on messages for user 1. The external shared message combiner then combines all users' split messages W1. 1234 , W2 1234 , W3 1234 and W4 1234 Combines. The first group shared message combiner is W1 12 , W2 12 Combines. The second group shared message combiner is W3 34 , W4 34Combine. Users can receive signals in which each of the external shared message, the first group shared message, the second group shared message, and the private messages is encoded through an encoder and then precoded through a linear precoder.

[0169] All users share a codebook that can decode external shared messages. Therefore, each user first decodes the external shared messages from the received signal. Users can remove the decoded external shared messages from the received signal using the sequential interference cancellation technique. Therefore, each user can generate a shared signal with the external shared messages removed. Thereafter, group shared messages and individual messages can be decoded in the same manner as the 1-layer structure. For example, users 1 and 2 decode the first group message, remove the first group message through sequential interference cancellation, and then decode their individual messages. Users 3 and 4 decode the second group message, remove the second group message through sequential interference cancellation, and then decode their individual messages. To this end, users belonging to group 1 must share a codebook that can decode the first group message, and users belonging to group 2 must share a codebook that can decode the second group message.

[0170] Using the above-described 2-layer HRS structure, the base station can transmit external shared messages, first group messages, second group messages, and individual messages through the same frequency resources and time resources using RSMA technology.

[0171] In the above-described 2-layer HRS structure, the first group can be classified as a RIS user group, and the second group can be classified as a direct user group. As described above, RIS can be used to cover shadow areas or increase coverage, and RIS includes RIS elements that can adjust the phase of reflected signals. The base station can transmit the reflection pattern to the RIS to control the RIS elements. Below, the procedure for the base station to control the RIS through an RRC connection will be described.

[0172] FIG. 16 illustrates an example of a procedure in which a base station controls an RIS via an RRC connection according to one embodiment of the present disclosure. Referring to FIG. 16 , a base station (1610) can connect to an RIS (1630) via an RIS control unit (1620).

[0173] In step S1601, the RIS control unit (1620) transmits a PRACH preamble (MSG1) to the base station (1610). To this end, the RIS control unit (1620) may first perform synchronization with the base station (1610). The RIS control unit (1620) may determine the PRACH preamble based on the MIB and SIB1 received through the synchronization process.

[0174] In step S1603, the base station (1610) transmits a random access response (RAR) message to the RIS control unit (1620). The RAR message may include a timing difference (time advance, TA) and a cell-radio network temporary identify (C-RNTI) assigned to the terminal.

[0175] In step S1605, the RIS control unit (1620) transmits an RRC setup request message to the base station (1610). The RIS control unit (1620) may transmit the RRC setup request message based on information about radio resource allocation included in the received RAR message. The RIS control unit (1620) may randomly determine a unique identifier for contention resolution. The RRC setup request message may include a unique identifier of the RIS control unit (1620) for contention resolution. In addition, the RRC setup request message may include an information element (IE) that enables the terminal and the RIS to be distinguished. For example, if the EstablishmentCause is included in the IE of the RRC request message, and the RIS control unit (1620) performs a communication connection with the base station (1610), a value indicating ris-Access may be assigned to the EstablishmentCause.

[0176] In step S1607, the base station (1610) transmits an RRC setup message to the RIS control unit (1620). The RRC setup message may include a unique identifier of the RIS control unit (1620) included in the RRC setup request message.

[0177] In step S1609, if the random access contention is resolved, the RIS control unit (1620) transmits an RRC setup complete message to the base station (1610). The RIS control unit (1620) can determine that the random access contention is resolved if its own unique identifier matches the unique identifier included in the RRC setup request message. The RRC setup complete message may include an IE indicating that a connection is being established by the RIS control unit (1620). For example, the RRC setup complete message may include an IE indicating that the connection is being established by the RIS control unit (1620), ris-NodeIndication-rxx, and a value indicating true may be assigned to ris-NodeIndication-rxx.

[0178] In step S1611, the base station (1610) transmits a capability inquiry message (e.g., UECapabilityEnquiry) to the RIS control unit (1620) to determine the capabilities of the RIS control unit (1620). The base station (1610) may request resource information of the RIS (1630) to identify available RIS communication channels. The resource information of the RIS (1630) may include information regarding the reflection pattern of the RIS (1630).

[0179] At step S1613, the RIS control unit (1620) transmits a capability information message (e.g., UECapabilityInformation) to the base station (1610). The capability information message may include information about the RIS element and may include information about a changeable beam phase shift of the RIS (1630).

[0180] At step S1615, the base station (1610) may transmit an RRC connection reconfiguration message to the RIS control unit (1620). The base station (1610) may change the communication channel using the RIS (1630) by modifying the settings for the RRC connection. The RRC connection reconfiguration message may include at least one of information necessary for a wireless communication connection, such as radio bearer setup and RRC reconfiguration conditions.

[0181] At step S1617, the RIS control unit (1620) completes communication setup based on the RRC connection reconfiguration message and then transmits an RRC connection reconfiguration complete message to the base station (1610).

[0182] In step S1619, the base station (1610) transmits a beam phase change request message to the RIS control unit (1620) to change the RIS channel environment. In step S1613, the base station (1610) can determine the reflection pattern of the RIS (1630) through the beam phase change request message received by the base station (1610).

[0183] In step S1621, the RIS control unit (1620) controls the elements of the RIS (1630) based on the beam phase change request message received in step S1619.

[0184] In step S1623, the RIS control unit (1620) transmits a beam phase change response message to the base station (1610). By receiving the beam phase change response message, the base station (1610) can confirm that the reflection pattern of the RIS (1630) has changed. Thereafter, the base station can perform communication with the terminal using the RIS channel.

[0185] Using the above-described procedure, the base station can identify the RIS through the RRC connection procedure, and security or authentication procedures between the RIS and the core network can be omitted. In other words, the RIS can be exclusively controlled by the base station, and in this case, the RIS does not need to exchange data with the core network, so security and authentication procedures can be omitted.

[0186] Additionally, the RIS can transmit available reflection pattern information to the base station. The base station can then receive this available reflection pattern information via the UE capability information message. Based on the received available reflection pattern information, the base station can perform reflection pattern control and reflection pattern optimization.

[0187] RIS can be categorized into the passive component portion of RIS and the RIS control unit. In this case, the base station can perform an RRC connection procedure with the RIS control unit. If a communication environment is established in which the base station can control RIS, the base station can use RIS to find RIS reflection patterns that can improve the channel environment of user terminals. The base station can utilize channel state information or measurement gaps to optimize the RIS reflection pattern.

[0188] FIG. 17 illustrates an example of an environment in which a 2-layer HRS structure and RIS user grouping are combined according to an embodiment of the present disclosure. Referring to FIG. 17, a base station (1710) can transmit RSMA signals using a 2-layer HRS structure to terminals using RIS (1720). In FIG. 17, the base station (1710) measures RIS channels corresponding to available RIS reflection patterns, and the number of available RIS reflection patterns is assumed to be M and described. The base station (1710) can classify each terminal into a RIS user group (1730#2) and a direct user group (1730#1) based on the M RIS channels measured by each terminal.

[0189] A terminal can measure channel gain values ​​of M RIS channels, and a dispersion of the channel gain values ​​may occur. The existence of a dispersion of the channel gain values ​​measured by each terminal means that the channel state may change due to RIS (1720). Therefore, the base station (1710) can classify terminals whose channel gain value increases due to RIS (1720) into a RIS user group (1730#2). Since RIS (1720) can be used when a terminal exists in a shadow area or to overcome a deteriorated channel environment, the base station (1710) can select a RIS reflection pattern having a channel gain value suitable for the purpose. The method of determining the RIS reflection pattern is not limited to a specific method. For example, the base station (1710) can select the RIS reflection pattern having the largest channel gain value among the channel gain values ​​measured by all terminals. As another example, the base station (1710) can select the RIS reflection pattern having the largest number of terminals having a channel gain value higher than a threshold value. The channel between the RIS (1720) and the terminal with the RIS reflection pattern selected by the base station (1710) can be formed. The base station (1710) can classify terminals whose normalized channel gain value is larger than the channel gain value in the absence of RIS (1720) in the selected RIS reflection pattern environment and whose dispersion is larger than a preset threshold value into the RIS user group (1730#2), and the remaining terminals can be classified into the direct user group (1730#1). Accordingly, when RIS (1720) is used, the channel gain value increases, and terminals that are relatively more affected by RIS (1720) belong to the RIS user group (1730#2).

[0190] Thereafter, the base station (1710) can transmit an RSMA signal using the 2-layer HRS structure as described above in FIG. 15. Accordingly, the direct user group (1730#1) can correspond to the first group of FIG. 15, and the RIS user group (1730#2) can correspond to the second group of FIG. 15. Accordingly, the base station (1710) can use the external shared message of RSMA for the purpose of transmitting common information to all users, the first group internal shared message can be used for the purpose of transmitting information to the direct user group (1730#1), and the second group internal shared message can be used for the purpose of transmitting information to the RIS user group (1730#2). In addition, the personal message can be used for the purpose of transmitting different information to each terminal.

[0191] Downlink RSMA signal Y received by the kth terminal using the RIS user group (1730#2) k can be expressed as in [Mathematical Formula 6] below.

[0192]

[0193] In [Equation 6], means the direct channel component between the base station (1710) and the kth terminal, means the channel between RIS (1720) and the kth terminal, refers to the channel between the base station (1710) and the RIS (1720), means the phase coefficient matrix of RIS(1720), means the power allocation coefficient corresponding to the external sharing message, means the power allocation coefficient of the group message, denotes the power allocation coefficient of the kth private message, means external shared message, means group sharing message, means the personal message of the kth terminal, means Gaussian noise. Therefore, may refer to a signal channel from a base station (1710) to a terminal through RIS (1720).

[0194] In an intelligent wireless environment such as Fig. 17, the number of controllable factors by a base station can be increased. Accordingly, the base station can use the phase coefficient matrix of RIS as a channel control factor and adjust the power allocation coefficient for message streams used in a 2-layer HRS environment. In other words, the base station can effectively control interference between terminals by adjusting the ratio of messages according to the communication environment. Therefore, the base station can control the number of controllable factors in a downlink 2-layer HRS environment. Channel capacity can be increased through optimization of the fields. To this end, the base station can use an alternating optimization algorithm, and the alternating optimization technique can be performed by dividing the first subproblem of determining the reflection pattern for optimization using RIS and the second subproblem of determining the power allocation coefficient for optimization of RSMA.

[0195] The RIS phase coefficient matrix can be optimized to determine the RIS reflection pattern. There may be various methods for optimizing the RIS phase coefficient matrix and it is not limited to a specific method. For example, the base station can determine the RIS phase coefficient matrix based on measured channel information to divide each group into a direct user group and a RIS user group in a 2-layer HRS structure. The objective function for optimization can be determined based on the transmission rate, and the transmission rate sum for the kth terminal can be expressed as in [Mathematical Formula 7].

[0196]

[0197] In [Equation 7] means the external common message transmission rate of the kth terminal, means the group message transmission rate of the kth terminal, means the personal message transmission rate of the kth terminal.

[0198] Also, a weight vector for each terminal transmission rate By applying , it can be expressed as a problem of maximizing the weighted sum transmission rate as in [Mathematical Equation 8] below.

[0199]

[0200] In [Equation 8], represents the weight coefficient for the transmission rate of the kth terminal, refers to the ratio of external shared messages to group messages.

[0201] At this time, the method of performing the shift optimization algorithm is not limited to a specific method. For example, to perform the shift optimization algorithm, the base station first calculates the phase coefficient matrix. , and fix the message ratio and beamforming vector can be optimized using the WMMSE (weighted minimum mean square error) technique.

[0202] Here, the WMMSE technique is a technique for maximizing the total transmission rate in a multi-user multiple-input and multiple-output (MU-MIMO) system, and is a technique for maximizing the total transmission rate by minimizing the weighted mean squared error (WMSE) for the transmitted and received signals. Since the slope value of the WMSE is the same as the slope value of the total transmission rate for a specific optimized weight matrix, the total transmission rate can be maximized when the WMSE is minimized.

[0203] For example, the constraints for optimization can be expressed as in [Mathematical Formula 9] below.

[0204]

[0205] In [Equation 9], means the external common message transmission rate of the kth terminal, means the minimum achievable rate limit of the kth terminal, means the group message transmission rate of the kth terminal, refers to the achievable rate limit of the group message transmission rate, stands for beamformer vector, means the limit of the total transmitted power, means the sum of the transmission rates for the kth terminal, represents the minimum transmission rate demand for the kth terminal.

[0206] The base station can perform the procedure shown in [Table 2] below within the constraints of [Mathematical Formula 9].

[0207] WMMSE Optimization Algorithm 1. Initialization: n <- 0, 2. Repeatn ← n+1 A weight vector that fixes and minimizes WMSE Decided to decide Fixing and minimizing WMSE Decided to decide Based on Until decision 3. Return

[0208] Based on the above-described procedure, the base station can configure direct user groups and RIS user groups based on the measurement information of the RIS channel, and determine parameter values ​​for channel capacity optimization. However, channel changes may occur due to user movement, etc., and channel capacity may decrease as interference from terminals increases. In this case, the base station can perform resource allocation of message streams applied to RSMA signal transmission to optimize channel capacity. That is, the base station can optimize channel capacity by adjusting the common message ratio (CMR) and the private message ratio (PMR). The signal-to-noise ratio (SNR) of the terminal can be used to manage the CMR and PMR of downlink RSMA according to the channel status. As follows, the base station can determine the common message ratio and the private message ratio to satisfy the maximum-minimum fairness based on the SNR.

[0209] In high-SNR channel environments, base stations can improve communication performance by increasing the CMR, thereby reducing the impact of multi-user interference. In high-SNR channel environments, because the communication demands or performance of individual users are already satisfied, the PMR can be reduced to fairly distribute the overall system throughput. Conversely, in low-SNR channel environments, base stations can reduce the CMR and increase the PMR, allocating more resources to individual users.

[0210] In an RSMA communication environment, the signal-to-interference-and-noise ratio (SINR) can be used as a criterion for high and low SNR. Therefore, the base station can determine the message ratio for each direct user group and RIS user group created in the two-layer HRS structure, thereby reducing the burden of message ratio adjustment for all users. The method by which the base station and terminal share the reference SINR can be implemented in various ways and is not limited to a specific method.

[0211] For example, the base station can transmit an SINR code to the terminals. The SINR code can be transmitted in the form of a code or value representing the measured SINR value, and is not limited to a specific method. For example, the SINR code can be an index value mapped using a table based on at least one of the SS-SINR measured through the secondary synchronization signal (SSS) used by the terminal when performing a connection with the base station, or the CSI-SINR measured through the channel state information - reference signal (CSI-RS). The base station can determine the SINR code value based on the channel information reported by the terminal.

[0212] The base station can periodically transmit the SINR code of each direct user group and RIS user group. By adjusting the frequency at which the SINR code is transmitted through group messages, the base station can optimize the communication system's frequency.

[0213] Thereafter, the terminal can request a change in the message rate based on the received SINR code. For example, the terminal can determine the SINR change amount by comparing the updated SINR code received from the base station with the previously received SINR. If the change in SINR is higher than the SINR threshold, the terminal can request the base station to change the message rate. Therefore, the optimization frequency of the communication system can be adjusted not only by the SINR code transmission cycle but also by the size of the threshold. That is, if the threshold is set small, the base station can sensitively adjust the message rate to the channel condition. Therefore, if the channel environment changes significantly, there may be a need to increase the frequency of performing optimization. In this case, the base station can reset the SINR threshold to a low value and transmit the reset SINR threshold to the terminal. Conversely, if the channel environment changes little, the SINR threshold can be set high.

[0214] When the base station performs optimization and transmits a reference signal, etc. to the terminal, the terminal measures its current SNR. The terminal can request a change in the message rate, and the request for a change in the message rate can be determined in various ways based on the measured SNR. For example, if the measured SNR is higher than the reference SINR, the terminal and the base station can determine that increasing the CMR ratio to reduce the influence of interference between terminals can create optimization with a higher probability. Therefore, the base station can perform optimization starting from a value greater than the current message rate value rather than initializing the currently allocated CMR to a random value in the step of optimizing the message rate. For example, the base station can perform optimization by using the method shown in [Table 2]. can perform optimization at the initialization stage. Instead of initializing to a random value, the CMR can be determined as a value that increases. Conversely, if the SNR measured by the terminal is lower than the reference SINR, the base station can determine that the influence of interference is small, and in the optimization phase, it can increase the current PMR. can be determined. Therefore, the initialization value of the message rate can be determined based on the current message rate.

[0215] Additionally, the base station can perform optimization by limiting the scope of the optimization to each group. Therefore, the constraints in [Equation 9] can be limited to each group and its terminals. When optimization is performed by group, unintended impacts on other groups can be prevented. If optimization is not possible within a given group or does not meet certain quality requirements, optimization can be performed for all terminals, focusing on the ratio of externally shared messages, internally shared messages, and private messages.

[0216] FIG. 18 illustrates an example of a procedure for a terminal to receive an RSMA signal of a two-layer HRS structure according to one embodiment of the present disclosure. Referring to FIG. 18, a terminal may belong to a specific group based on channel measurements and may receive a signal comprising an external shared message, an internal shared message, and a private message.

[0217] In step S1801, the terminal receives a reference signal from the base station. The terminal can perform measurements based on the reference signal received from the base station. The reference signal can be transmitted periodically and is not limited to a specific signal. For example, the reference signal can use at least one of SSS or CSI-RS.

[0218] In step S1803, the terminal transmits a channel measurement report to the base station. The channel measurement report may be transmitted in the form of an RRC message. The channel measurement report message may include information about the results of measurements performed by the terminal based on a reference signal.

[0219] Steps S1801 and S1803 may be performed repeatedly. The base station may classify terminals into direct user groups and RIS user groups to implement an RSMA system having a two-layer HRS structure. As described above, the method for classifying terminals into direct user groups and RIS user groups may be determined based on the variance of measured channel gain values. To classify terminals into direct user groups and RIS user groups, the terminals may receive reference signals and transmit channel measurement report messages. In addition, for the base station to update information about SINR, the terminals may periodically receive reference signals and transmit channel measurement report messages.

[0220] In step S1805, the terminal receives information about SINR from the base station. The information about SINR can be transmitted in various ways. For example, the information about SINR can be transmitted in the form of an SINR code or an SINR value. The SINR code can be mapped using a table based on at least one of the SS-SINR measured through the secondary synchronization signal (SSS) used by the terminal when connecting to the base station or the CSI-SINR measured through the CSI-RS. Accordingly, the SINR code value can be transmitted as an index value mapped based on the table. In addition, if channel measurement is performed periodically, the terminal can periodically receive information about SINR from the base station.

[0221] In step S1807, the terminal requests the base station to change the message ratio based on information about the SINR. Step S1807 may be configured to be performed only when a specific condition is satisfied. For example, the terminal may request the base station to change the message ratio when the amount of change in the SINR is greater than a specific threshold. The message ratio is a ratio of at least one of the first shared message, the second shared message, the third shared message, or the private messages, and may be referred to as CMR or PMR. The terminal may request the base station to increase the CMR or PMR based on the SNR measured by the terminal. The base station may optimize the beamformer, the RIS reflection pattern, and the message ratio based on the message ratio change request received from the terminal. The optimization may utilize the WMMSE technique described in [Table 2]. For optimization, the beamformer may be expressed as a beamforming vector, the RIS reflection pattern may be expressed as a phase coefficient matrix, and the message ratio may be expressed as a vector including at least one of an external shared message, an internal shared message, or a private message.

[0222] In step S1809, the terminal receives an RSMA signal from the base station. In an RSMA system having a two-layer HRS structure, the RSMA signal may include an external shared message, an internal shared message, and individual messages. The base station may generate and combine the external shared message, the internal shared message of the direct user group, the internal shared message of the RIS user group, and the individual messages of each terminal based on the determined message ratio, and transmit the RSMA signal. A message distributor and a message combiner may be utilized to generate and transmit the RSMA signal, as described above with reference to FIGS. 14 and 15 .

[0223] Thereafter, the terminal can decode the RSMA signal through sequential interference cancellation. For example, if the terminal belongs to the RIS user group, the terminal can decode the external sharing message using the codebook for the external sharing message in the received first RSMA signal. Thereafter, the terminal can perform a sequential interference cancellation technique using the received first RSMA and the external sharing message to generate a second RSMA signal excluding the external sharing message. The terminal can then decode the internal sharing message of the RIS user group using the codebook for the internal sharing message of the RIS user group in the second RSMA signal. The terminal can then perform a sequential interference cancellation technique using the second RSMA signal and the internal sharing message of the RIS user group to generate a third RSMA signal excluding the internal sharing message from the second RSMA signal. Thereafter, the terminal can decode the third RSMA signal using a codebook for a personal message assigned to each terminal.

[0224] FIG. 19 illustrates an example of a procedure for a base station to transmit an RSMA signal of a two-layer HRS structure according to one embodiment of the present disclosure. Referring to FIG. 19 , the base station can transmit a signal consisting of an external shared message, an internal shared message, and a private message.

[0225] In step S1901, the base station transmits a reference signal to the terminal. The reference signal may be transmitted periodically and is not limited to a specific signal. For example, the reference signal may use at least one of SSS or CSI-RS.

[0226] In step S1903, the base station receives a channel measurement report from the terminal. The channel measurement report may be transmitted in the form of an RRC message. The channel measurement report message may include information about the results of measurements performed by the terminal based on a reference signal.

[0227] Steps S1901 and S1903 may be performed repeatedly. The base station may classify terminals into direct user groups and RIS user groups to implement an RSMA system having a two-layer HRS structure. As described above, the method for classifying terminals into direct user groups and RIS user groups may be determined based on the variance of measured channel gain values. In order for the base station to classify terminals into direct user groups and RIS user groups, the terminals may receive reference signals and transmit channel measurement report messages. In addition, in order for the base station to update information about SINR, the terminals may periodically receive reference signals and transmit channel measurement report messages.

[0228] In step S1905, the base station transmits information about the SINR to the terminal. The information about the SINR can be transmitted in various ways. For example, the information about the SINR can be transmitted in the form of an SINR code or an SINR value. The SINR code can be mapped using a table based on at least one of the SS-SINR measured through the SSS used by the terminal when connecting to the base station or the CSI-SINR measured through the CSI-RS. As described above, if channel measurement is performed periodically, the terminal can periodically receive information about the SINR from the base station.

[0229] In step S1907, the base station receives a message rate change request from the terminal. Step S1907 may be configured to be performed only when certain conditions are met. For example, the terminal may request the base station to change the message rate if the change in SINR exceeds a certain threshold.

[0230] In step S1909, the base station changes the message ratio. The message ratio is a ratio of at least one of the first shared message, the second shared message, the third shared message, or the private messages, and may be referred to as CMR or PMR. The base station may optimize the beamformer, the RIS reflection pattern, and the message ratio based on the message ratio change request received from the terminal. The optimization may utilize the WMMSE technique described in [Table 2]. For optimization, the beamformer may be expressed as a beamforming vector, the RIS reflection pattern may be expressed as a phase coefficient matrix, and the message ratio may be expressed as a vector including at least one of an external shared message, an internal shared message, or a private message.

[0231] In step S1911, the base station can transmit an RSMA signal to the terminal. In an RSMA system having a 2-layer HRS structure, the RSMA signal can include an external shared message, an internal shared message, and an individual message. The base station can generate and combine the external shared message, the internal shared message of the direct user group, the internal shared message of the RIS user group, and the individual messages of each terminal based on the determined message ratio, and transmit the RSMA signal. A message distributor and a message combiner can be utilized as described above with reference to FIGS. 14 and 15 to generate and transmit the RSMA signal. The base station can optimize the beamformer, the RIS reflection pattern, and the message ratio in various ways, and can determine the initial settings using the parameter values ​​that were previously used based on the CMR or PMR increase request transmitted by the terminal.

[0232] FIG. 20 illustrates an example of signaling between a base station (2010) and a terminal (2030) for optimizing transmission and reception of RSMA signals based on variations in SINR values ​​according to one embodiment of the present disclosure. In FIG. 20, it is assumed that the base station (2010) receives a measurement report from the terminal (2030) and classifies the terminals (2030) into a direct user group and an RIS user group.

[0233] In step S2001, the base station (2010) determines an SINR value through channel measurement and determines a table regarding SINR codes. The table regarding SINR codes can be used to determine an SINR code status indicator.

[0234] In step S2003, the base station (2010) transmits an SINR code status indicator to the terminal (2030). The base station (2010) may transmit the SINR value directly to the terminal (2030), but may also transmit it in the form of an SINR code status indicator. The SINR code status indicator may be determined using an index value based on an SINR code table. Accordingly, the terminal (2030) can obtain a reference SINR value based on the SINR code status indicator.

[0235] In step S2005, the terminal (2030) determines the change in the SINR value. To this end, the terminal (2030) must store the previously received SINR value or SINR code status indicator.

[0236] In step S2007, the terminal (2030) requests the base station (2010) to change the message rate. The terminal (2030) can first measure its own SNR value. If the measured SNR value is greater than the reference SINR value, the terminal can request the base station (2010) to increase the CMR. Conversely, if the measured SNR value is less than the reference SINR value, the terminal can request the base station (2010) to increase the PMR. The reference SINR value can be determined in various ways. For example, the average SINR value for all terminals (2030) can be used as the reference SINR value. In another example, the reference SINR value can be applied to each group, and the average SINR value calculated for each group can be used. Therefore, if the terminal (2030) belongs to the RIS user group, the reference SINR value can be the average SINR value measured by the terminals (2030) belonging to the RIS user group.

[0237] In step S2007, the base station (2010) performs optimization of the beamformer, RIS reflection pattern, and message rate. The base station (2010) may first perform optimization within the direct user group or the RIS user group. For example, if the terminal (2030) belongs to the RIS user group, the base station (2010) may perform optimization by limiting the power constraint conditions for optimization to conditions for the RIS user group and the terminals (2030) in the RIS user group. Accordingly, the base station (2010) may maintain the external shared message rate and change the internal shared message rate and individual message rates of each group by considering only the power constraint conditions related to the group in which the terminal is included.

[0238] If the communication environment still does not meet certain quality requirements even after optimization, additional optimization may be required. In this case, the base station (2010) can perform optimization targeting all terminals (2030). Accordingly, the base station (2010) can change the external shared message ratio, the internal shared message ratio by group, and the individual message ratio.

[0239] FIG. 21 illustrates an example of signaling between a base station, an RIS, and terminals (2030#1, 2030#2) for transmitting RSMA signals based on grouping, according to one embodiment of the present disclosure. Referring to FIG. 21, the base station can group terminals based on distribution and transmit RSMA signals to the terminals.

[0240] In step S2101, the base station, RIS, first terminal, and second terminal perform an RRC connection procedure. If the RIS control unit is configured separately, the base station can perform an RRC connection procedure with the RIS control unit. Furthermore, the method by which the base station controls the RIS does not necessarily involve an RRC connection and is not limited to a specific method.

[0241] In steps S2103#1 to S2103#n, the base station can perform n channel measurements. If the number of changeable RIS reflection patterns is n, the base station can repeat the measurement procedure to measure all n channels. At this time, the first channel may be a channel in which the RIS is turned off. Therefore, the first channel may mean a direct channel between the base station and the terminals. The base station can transmit a first reflection pattern in which all elements are set not to change phase to the RIS, and transmit a first reference signal to the terminals. The base station can receive first channel measurement information from each of the terminals. The measurement procedure can be repeated multiple times. The base station can receive available reflection patterns from the RIS and measure RIS channels corresponding to each of the reflection patterns.

[0242] In step S2105, the base station classifies the terminals into a direct user group and a RIS user group. The base station can perform grouping based on the channel gain values ​​corresponding to each channel measured by the terminals in steps S2103#1 to S2103#n. For example, if the variance of the channel gain value measured by the first terminal is large, the base station can determine that the terminal is greatly affected by RIS and classify the first terminal into the RIS user group. In addition, if the channel gain value measured by the second terminal is high but the variance value is low, the base station can determine that the terminal is not affected by RIS and classify the second terminal into the direct user group. For convenience of the following explanation, it is assumed that the first terminal is classified into the direct user group and the second terminal is classified into the RIS user group.

[0243] In step S2107, the base station optimizes beamforming, reflection pattern, and message rate. At this time, the base station can use the procedures described in [Table 2].

[0244] At step S2109, the base station can transmit an RSMA signal based on the optimized parameters. The base station can transmit the determined reflection pattern to the RIS and transmit the RSMA signal using a two-layer HRS structure based on the determined message rate. If the channel environment changes, the base station can re-perform optimization. Accordingly, the procedures described in FIGS. 18 to 20 can be repeated.

[0245] The RSMA communication system using RIS proposed in this disclosure can increase spectral efficiency despite the limitations of channel capacity due to characteristics of the wireless channel. Furthermore, the RSMA communication system using RIS can efficiently transmit signals to terminals in shadow areas. Furthermore, to utilize the 2-layer HRS technique, an extension technology of RSMA, the base station can perform RIS user grouping and direct user grouping. Furthermore, when the channel changes due to movement of terminals, etc., the base station can efficiently optimize channel capacity by adjusting the RSMA message rate, thereby further increasing spectral efficiency.

[0246] It is clear that the examples of the proposed methods described above can also be considered as a type of proposed methods, as they can be included as one of the implementation methods of the present disclosure. Furthermore, the proposed methods described above can be implemented independently, but they can also be implemented in the form of a combination (or merge) of some of the proposed methods. Information regarding the applicability of the proposed methods (or information regarding the rules of the proposed methods) can be defined by a rule such that the base station notifies the terminal of the application of the proposed methods through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0247] 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 do not explicitly cite each other in the claims may be combined to form embodiments or incorporated into new claims through post-filing amendments.

[0248] 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.

[0249] 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.

[0250] 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 terminal in a wireless communication system, A step of receiving a first reference signal for measuring a first channel from a base station; A step of transmitting a first measurement report message based on the first reference signal to the base station; A step of receiving information on a signal to interference and noise ratio (SINR) value from the base station; A step of requesting a change in message rate based on the SINR value to the base station; and Comprising a step of receiving a data signal from the above base station, The terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, A method of operating a terminal, wherein the data signal comprises a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and private messages decoded by each of the terminals.

2. In paragraph 1, The above first measurement report message includes the channel gain value of the first channel, A method of operating a terminal, wherein the terminal is included in a first group based on a distribution of channel gain values ​​measured by the terminal by the base station.

3. In paragraph 1, The above data signal is transmitted through the RSMA (rate splitting multiple access) technique, A method of operating a terminal, wherein the first shared message, the second shared message, the third shared message and the private message are transmitted through the same frequency resource and time resource.

4. In paragraph 1, A step of receiving information about an updated SINR value from the base station; and Further comprising a step of determining the amount of change in the SINR value based on the updated SINR value, A method of operating a terminal, wherein a request for changing the message rate is performed based on a case where the amount of change in the SINR value is greater than a SINR threshold value.

5. In paragraph 4, If the frequency of message rate changes needs to be changed, A method of operating a terminal, wherein the terminal receives a reset SINR threshold value from the base station.

6. In paragraph 1, A request to change the message ratio includes either a request to increase the common message ratio (CMR) or a request to increase the private message ratio (PMR). The above CMR increase request is a request for an increase in the ratio of at least one of the first shared message, the second shared message or the third shared message, A method of operating a terminal, wherein the above PMR increase request is a request for an increase in the ratio of personal messages of the terminal.

7. In paragraph 6, If the SNR measured by the terminal is greater than the SINR value, the request for changing the message rate includes a request for increasing the CMR, A method of operating a terminal, wherein the request for changing the message rate includes a request for increasing a PMR when the SNR measured by the terminal is less than the SINR value.

8. In paragraph 1, If the terminal is included in the first group, the SINR value is determined as an average value of the SINR values ​​measured by the terminals belonging to the first group, A method of operating a terminal, wherein, when the terminal is included in the second group, the SINR value is determined as an average value of SINR values ​​measured by terminals belonging to the second group.

9. In paragraph 1, A method of operating a terminal, wherein the above SINR value is determined based on at least one of SS-SINR measured through SSS (secondary synchronization signal) or CSI-SINR measured through CSI-RS (channel state information - reference signal).

10. In paragraph 1, The information about the above SINR value includes the SINR code value, A method of operating a terminal, wherein the above SINR code value is an index value mapped using a table.

11. In paragraph 1, A method of operating a terminal, wherein a beamformer, a RIS reflection pattern and the message ratio are determined by the base station based on a request for a change in the message ratio.

12. In paragraph 11, The beamformer, the RIS reflection pattern and the message ratio are determined by the WMMSE (weighted minimum mean square error) technique. The above WMMSE technique initializes the beamformer, the RIS reflection pattern and the message rate, A method of operating a terminal, the method comprising: determining the beamformer, the RIS reflection pattern, and the message ratio so that the weighted mean squared error (WMSE) for the transmitted signal and the received signal is minimized so that the total transmission rate is maximized.

13. In paragraph 12, A method of operating a terminal, wherein the initialization value of the above message ratio is determined based on the above message ratio.

14. In a method of operating a base station in a wireless communication system, A step of transmitting a first reference signal for measuring a first channel to a terminal; A step of receiving a first measurement report message based on the first reference signal from the terminal; A step of transmitting information about a SINR (signal to interference and noise ratio) value to the terminal; A step of receiving a request for changing a message rate based on the SINR value from the terminal; A step of changing the message ratio based on a request for changing the message ratio; and Including a step of transmitting a data signal to the above terminal, The terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, A method of operating a base station, wherein the data signal comprises a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and private messages decoded by each of the terminals.

15. In paragraph 14, A step of performing the above RIS and RRC (radio resource control) connection; A step of transmitting a RIS reflection pattern to the above RIS; A step of transmitting a second reference signal for measuring a second channel to the terminal; A step of receiving a second measurement report message based on the second reference signal from the terminal; and Further comprising a step of classifying the terminal into one of the first group or the second group, A method of operating a base station, wherein the above classification is determined based on the variance of channel gain values ​​measured by the terminal.

16. In paragraph 15, Further comprising the step of receiving a capability information message from the above RIS, The above capability information message contains available reflection pattern information, A method of operating a base station, wherein the above RIS reflection pattern is determined based on the available reflection pattern information.

17. In paragraph 14, The above base station further includes a step of determining a beamformer, a RIS reflection pattern and the message rate based on a request for changing the message rate, A method of operating a base station, wherein the beamformer, the RIS reflection pattern and the message ratio are determined only by considering power constraints related to the group including the terminal.

18. In a wireless communication system, at a terminal, Transmitter and receiver; and comprising a processor connected to the above transceiver, The above processor, Receive a first reference signal for measuring a first channel from a base station, Transmitting a first measurement report message to the above base station based on the above first reference signal, Receive information about the SINR (signal to interference and noise ratio) value from the above base station, and requesting the base station to change the message rate based on the SINR value. Control to receive a data signal from the above base station, The terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, A terminal, wherein the data signal comprises a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and private messages decoded by each of the terminals.

19. In a base station in a wireless communication system, Transmitter and receiver; and comprising a processor connected to the above transceiver, The above processor, Transmitting a first reference signal to the terminal for measuring the first channel, Receive a first measurement report message based on the first reference signal from the terminal, Transmit information about the SINR (signal to interference and noise ratio) value to the above terminal, Receive a request to change the message rate based on the SINR value from the terminal, Changing the message ratio based on a request to change the message ratio, and Control to transmit a data signal to the above terminal, The terminal is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the terminal based on the first measurement report message, or a second group using a direct channel between the terminal and the base station, A base station, wherein the data signal comprises a first shared message decoded by terminals belonging to the first group and the second group, a second shared message decoded by terminals belonging to the first group, a third shared message decoded by terminals belonging to the second group, and private messages decoded by each of the terminals.

20. In communication devices, At least one processor; At least one computer memory coupled to said at least one processor and storing instructions that direct operations when executed by said at least one processor, The above actions are, A step of receiving a first reference signal for measuring a first channel from a base station; A step of transmitting a first measurement report message based on the first reference signal to the base station; A step of receiving information on a signal to interference and noise ratio (SINR) value from the base station; A step of requesting a change in message rate based on the SINR value to the base station; and Comprising a step of receiving a data signal from the above base station, The communication device is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the communication device based on the first measurement report message or a second group using a direct channel between the communication device and the base station, A communication device, wherein the data signal comprises a first shared message decoded by communication devices belonging to the first group and the second group, a second shared message decoded by communication devices belonging to the first group, a third shared message decoded by communication devices belonging to the second group, and private messages decoded by each of the communication devices.

21. 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: Receive a first reference signal for measuring a first channel from a base station, Transmitting a first measurement report message to the above base station based on the above first reference signal, Receive information about the SINR (signal to interference and noise ratio) value from the above base station, and requesting the base station to change the message rate based on the SINR value. Control to receive a data signal from the above base station, The device is included in either a first group using the first channel including a channel between the base station and a reconfigurable intelligent surface (RIS) and a channel between the RIS and the device based on the first measurement report message or a second group using a direct channel between the device and the base station, A computer-readable medium, wherein the data signal comprises a first shared message decoded by devices belonging to the first group and the second group, a second shared message decoded by devices belonging to the first group, a third shared message decoded by devices belonging to the second group, and private messages decoded by each of the devices.

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