Method and apparatus for transmitting or receiving DFT-spread OFDM signal by performing channel-dependent frequency-domain spectrum shaping in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A DFT-spread OFDM transmitter according to an embodiment receives, from a DFT-spread OFDM receiver, information about generation of a channel-based transmission spectrum shaping vector, determines a channel-dependent transmission spectrum shaping vector on the basis of the received information, generates a DFT-spread-OFDM signal including at least one symbol on basis of the determined channel-dependent transmission spectrum shaping vector, and transmits the generated DFT-spread-OFDM signal to the receiver, wherein the channel-dependent transmission spectrum shaping vector may be determined to minimize a linear minimum mean square error (LMMSE) on basis of channel information and interference-noise information if an LMMSE optimization criterion is set.

Description

Method and apparatus for transmitting and receiving DFT-SPREAD OFDM signals by performing channel-dependent frequency domain spectrum shaping in a wireless communication system

[0001] The present disclosure relates to a technology for transmitting and receiving DFT-spread OFDM signals in a wireless communication system, and more specifically, provides a method and apparatus for performing channel-dependent (CD) frequency-domain spectrum shaping (FDSS).

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, implementation in the terahertz band (e.g., the 3 terahertz (3 THz) band at 95 GHz) is being considered to achieve transmission speeds 50 times faster and ultra-low latency reduced to one-tenth compared to 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X (Vehicle-to-Everything), which helps autonomous vehicles make driving decisions and enhance user convenience based on their own location and status information transmitted by the vehicle; NR-U (New Radio Unlicensed), which aims for system operation in unlicensed bands to comply with various regulatory requirements; NR terminal low power consumption technology (UE Power Saving); Non-Terrestrial Network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

[0005] In addition, standardization is underway in the field of wireless interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) for supporting new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) Handover, and 2-step Random Access (2-step RACH for NR) which simplifies random access procedures. Standardization is also underway in the field of system architecture / services for 5G baseline architectures (e.g., Service based Architecture, Service based Interface) for incorporating Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC), which provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms to guarantee coverage in the terahertz band of 6G mobile communication technology, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas; metamaterial-based lenses and antennas to improve terahertz band signal coverage; high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum); and Reconfigurable Intelligent Surface (RIS) technology; as well as Full Duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] The present disclosure is intended to provide optimal transmit / receive spectrum shaping vectors in the frequency domain for DFT-spread OFDM signals.

[0009] A DFT-spread OFDM transmitter according to one embodiment receives information regarding the generation of a channel-based transmit spectrum forming vector from a DFT-spread OFDM receiver, determines a channel-dependent transmit spectrum forming vector based on the received information, generates a DFT-spread-OFDM signal including at least one symbol based on the determined channel-dependent transmit spectrum forming vector, and transmits the generated DFT-spread-OFDM signal to the receiver. The channel-dependent transmit spectrum forming vector may be determined such that the LMMSE (linear minimum mean square error) is minimized based on information regarding the channel and information regarding interference-noise when an LMMSE optimality criterion is set.

[0010] According to the present disclosure, a transceiver performing optimal channel-dependent transmit / receive spectrum shaping can exhibit higher performance than a transceiver not performing channel-dependent transmit / receive spectrum shaping by selecting subcarriers with higher signal-to-noise ratios in a frequency-selective channel environment. Furthermore, the optimal channel-dependent transmit / receive spectrum shaping vector according to the present disclosure can achieve higher performance than a transceiver not performing channel-dependent transmit / receive spectrum shaping by finding a subspace with a higher signal-to-interference-plus-noise ratio (SINR) in the presence of data-like interference and appropriately allocating transmit power or energy.

[0011] FIG. 1 is a block diagram showing the configuration of a DFT-spread OFDM transmitter that performs channel-dependent frequency-domain spectrum shaping (CD-FDSS) according to one embodiment of the present disclosure.

[0012] FIG. 2 is a diagram illustrating the DFT-spread section of a DFT-spread OFDM transmitter that performs CD-FDSS according to one embodiment of the present disclosure.

[0013] FIG. 3 is a diagram illustrating a circular expansion section of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0014] FIG. 4 is a diagram illustrating a channel-dependent frequency domain spectrum shaping unit and a transmission spectrum shaping vector generation unit of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0015] FIG. 5 is a diagram illustrating a subcarrier allocation unit of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0016] FIG. 6 is a flowchart of a DFT-spread OFDM transmission method for performing CD-FDSS according to one embodiment of the present disclosure.

[0017] FIG. 7 is a block diagram showing the configuration of a DFT-spread OFDM receiver that receives a signal to which CD-FDSS is applied according to one embodiment of the present disclosure.

[0018] FIG. 8 is a flowchart of a DFT-spread OFDM receiving method according to one embodiment of the present disclosure.

[0019] FIG. 9 shows the optimal reception spectrum-shaping vector of a DFT-spread OFDM receiver according to one embodiment of the present disclosure. This is a flowchart to explain how to find it.

[0020] FIG. 10 is an optimal transmit spectrum-shaping vector of a DFT-spread OFDM transmitter according to one embodiment of the present disclosure. This is a flowchart to explain how to find it.

[0021] FIG. 11 is a drawing for explaining a DFT-spread OFDM communication system according to one embodiment of the present disclosure.

[0022] FIG. 12 is a diagram illustrating a method for transmitting and receiving a DFT-spread OFDM signal with an optimal spectrum shaping vector applied in a transmitter and a receiver according to one embodiment of the present disclosure.

[0023] FIG. 13 is a block diagram of a transmitter according to one embodiment of the present disclosure.

[0024] FIG. 14 is a block diagram of a receiver according to one embodiment of the present disclosure.

[0025] A DFT-spread OFDM transmitter according to one embodiment of the present disclosure comprises: at least one transceiver; at least one processor communicably coupled to at least one transceiver; and a memory communicably coupled to at least one processor and storing one or more instructions, wherein when the one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM transmitter receives information regarding the generation of a transmission spectrum forming vector based on a channel between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver from a DFT-spread OFDM receiver, determines a channel-dependent transmission spectrum forming vector based on the received information, generates a DFT-spread-OFDM signal including at least one symbol based on the determined channel-dependent transmission spectrum forming vector, and transmits the generated DFT-spread-OFDM signal to the receiver, wherein the channel-dependent transmission spectrum forming vector may be determined such that the LMMSE is minimized based on information regarding the channel and information regarding interference-noise when an LMMSE optimality criterion is set.

[0026] In a DFT-spread OFDM transmitter according to one embodiment of the present disclosure, when one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM transmitter may further: periodically expand a DFT-spread symbol vector comprising at least one symbol to generate a cyclically expanded vector; generate a frequency-domain spectrum-shaped vector based on the cyclically expanded vector and a channel-dependent-transmit spectrum-shaped vector; assign the frequency-domain spectrum-shaped vector to a subcarrier in an assigned frequency range; and generate a DFT-spread OFDM signal based on the vector assigned to the subcarrier.

[0027] In a DFT-spread OFDM transmitter according to one embodiment of the present disclosure, when one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM transmitter further: based on LMMSE optimality criteria, The positive number that is the unique solution of Using, the optimal energy distribution solution Acquire, The maximum value of the eigenvalues ​​of the matrix defined as class The eigenvector corresponding to and a function optimized to reduce PAPR Using vector Decide on, having the nth column According to mathematical formula 1, the length Vector created with ( ) is determined as the channel-dependent transmit spectrum shaping vector, and Equation 1 is , , is, is a matrix representing the channels, and is a matrix representing interference-noise, and is the length of the cyclically expanded vector, and is the number of at least one symbol.

[0028] In a DFT-spread OFDM transmitter according to one embodiment of the present disclosure, when one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM transmitter may further: determine an optimal channel-dependent-transmit spectrum forming vector by approximating the noise indicated by information regarding interference-noise to be small when a linear zero forced optimality criterion is set, and determine an optimal channel-dependent-transmit spectrum forming vector by approximating the interference indicated by information regarding interference-noise to be small when a linear matched filter optimality criterion is set.

[0029] In a DFT-spread OFDM transmitter according to one embodiment of the present disclosure, when one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM transmitter may further: determine an optimal channel-dependent-transmit spectrum forming vector satisfying the decision feedback optimality criterion based on information regarding the channel and information regarding interference-noise when a decision feedback optimality criterion is set, and determine an optimal channel-dependent-transmit spectrum forming vector satisfying the mutual information optimality criterion based on information regarding the channel and information regarding interference-noise when a mutual information optimality criterion is set.

[0030] In a DFT-spread OFDM transmitter according to one embodiment of the present disclosure, information regarding the generation of a transmit spectrum forming vector may include information regarding a channel and information regarding interference-noise, or may include a channel-dependent transmit spectrum forming vector calculated based on a channel-dependent receive spectrum forming vector determined by a DFT-spread OFDM receiver.

[0031] A DFT-spread OFDM receiver according to one embodiment of the present disclosure comprises: at least one transceiver; at least one processor communicably coupled to at least one transceiver; and a memory communicably coupled to at least one processor and storing one or more instructions, wherein when the one or more instructions are executed individually or in combination by at least one processor, the DFT-spread OFDM receiver determines information regarding a channel between a DFT-spread OFDM transmitter and a DFT-spread OFDM receiver and information regarding interference-noise, and when an LMMSE optimality criterion is set, determines a channel-dependent receive spectrum forming vector such that LMMSE is minimized based on the information regarding the channel and the information regarding interference-noise, transmits information regarding the generation of a channel-dependent transmit spectrum forming vector corresponding to the channel-dependent receive spectrum forming vector to a DFT-spread OFDM transmitter, and the channel-dependent transmit spectrum forming vector may be determined at the DFT-spread OFDM transmitter based on the information regarding the generation of the channel-dependent transmit spectrum forming vector.

[0032] A method performed by a DFT-spread OFDM transmitter according to one embodiment of the present disclosure comprises: receiving information from a DFT-spread OFDM receiver regarding the generation of a transmit spectrum forming vector based on a channel between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver; determining a channel-dependent transmit spectrum forming vector based on the received information; generating a DFT-spread OFDM signal including at least one symbol based on the determined channel-dependent transmit spectrum forming vector; and transmitting the generated DFT-spread OFDM signal to the receiver, wherein the channel-dependent transmit spectrum forming vector may be determined such that the LMMSE is minimized based on information regarding the channel and information regarding interference-noise when an LMMSE optimality criterion is set.

[0033] A method performed by a DFT-spread OFDM receiver according to one embodiment of the present disclosure comprises: a step of providing information regarding a channel between a DFT-spread OFDM transmitter and a DFT-spread OFDM receiver; a step of determining a channel-dependent receiving spectrum forming vector such that LMMSE is minimized based on information regarding the channel and information regarding interference-noise when an LMMSE optimality criterion is set; and a step of transmitting information regarding the generation of a channel-dependent transmitting spectrum forming vector corresponding to the channel-dependent receiving spectrum forming vector to a DFT-spread OFDM transmitter, wherein the channel-dependent transmitting spectrum forming vector may be determined in the DFT-spread OFDM transmitter based on information regarding the generation of the channel-dependent transmitting spectrum forming vector.

[0034] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0035] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0036] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual dimensions. Identical or corresponding components in each drawing have been assigned the same or different reference numbers.

[0037] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0038] In the present disclosure, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams may be performed based on computer program instructions. Since these computer program instructions may be optionally loaded into at least one processor of a general-purpose computer, a computer for special purposes, or other programmable data processing equipment, the instructions performed through any one or any combination of at least one processor of the computer or other programmable data processing equipment create means for performing the functions described in the flow diagram block(s). Since these computer program instructions may also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the functions in a specific manner, the instructions stored in computer-available or computer-readable memory may also produce a manufactured item containing means of instruction for performing the functions described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0039] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks (or functions) described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to the corresponding function.

[0040] As used in the embodiments of the present disclosure, the term “part” refers to a software or hardware component, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), and the “part” performs certain roles. However, the term including “part” is not limited to software or hardware. The “part” may be configured to reside in an addressable storage medium or may be configured to run on one or more processors. Thus, by example, the “part” includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and “parts” may be combined into a smaller number of components and “parts” or further separated into additional components and “parts.” In addition, the components and 'parts' may be implemented to utilize one or more CPUs (central processing units) within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0041] As stated above, it should be noted that the blocks of each flowchart and combinations of flowcharts described in this disclosure may be executed by one or more computer programs including instructions. The entirety of one or more computer programs may be stored in a single memory device, or one or more computer programs may be divided into different parts and stored across multiple memory devices.

[0042] Additionally, any / any function or operation described in this disclosure may be processed by a single processor or a combination of processors. The single processor or combination of processors is a circuitry that performs processing and may include an application processor (AP, e.g., a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural network processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near-field communication (NFC) chip, a connectivity chip, a sensor controller, a touch controller, a fingerprint sensor controller, a display driver integrated circuit (IC), an audio codec (CODEC) chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, a microprocessor unit (MPU), a system-on-chip (SoC), an IC, or similar circuitry.

[0043] Additionally, it should be noted that various embodiments in the claims and description of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0044] Such software may be stored on a non-transitory computer-readable storage medium. A non-transitory computer-readable storage medium stores one or more computer programs (software modules), and said one or more computer programs include computer-executable instructions that operate an electronic device to perform a method according to the present disclosure when executed alone or collectively by one or more processors of an electronic device.

[0045] The software may be stored in a transient or non-transient storage device, for example, in the form of read-only memory (ROM) (whether or not it is erasable or rewritable), or random access memory (RAM), memory chips, devices, or integrated circuits (ICs). Additionally, the software may be stored in the form of an optically or magnetically readable medium, for example, a compact disc (CD), a digital multifunction disc (DVD), a magnetic disc, or a magnetic tape. It should be understood that the storage device and the storage medium are examples of non-transient machine-readable storage media suitable for storing programs for implementing various embodiments of the present disclosure. Accordingly, various embodiments of the present disclosure may provide a program containing code for implementing a device or method according to any one of the claims of this specification, and a non-transient machine-readable storage medium storing such program.

[0046] In the following disclosure, determining the priority between A and B may be referred to in various ways, such as selecting the one with the higher priority according to a predetermined priority rule and performing the corresponding action, or omitting or dropping the action for the one with the lower priority.

[0047] Hereinafter, 'A or B' as described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0048] Additionally, 'at least one of A, B, and C' described in the present disclosure may be understood to include 'A', or 'B', or 'C', or 'any combination of A, B, and C'.

[0049] Additionally, 'at least one of A, B, or C' described in the present disclosure may be understood to include 'A', or 'B', or 'C', or 'any combination of A, B, and C'.

[0050] Additionally, 'A / B' as described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0051] Additionally, 'A, B' described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0052] Additionally, 'A and B' described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0053] Furthermore, the phrase "when conditions A and B are satisfied" as described in the present disclosure is not necessarily limited to cases where both conditions A and B are satisfied, but may be understood to include cases where either condition A or condition B is satisfied individually, cases where both conditions A and B are satisfied, or cases where one or more additional conditions are satisfied together.

[0054] Furthermore, throughout this specification, ordinal terms (and similar modifiers) such as 'first', 'second', 'third', etc. are used solely for the purpose of distinguishing various instances, occurrences, configurations, messages, stages, or aspects of elements, operations, or information, as described below. Unless clearly required otherwise by the context, the use of such ordinal terms does not require that the elements, operations, or information distinguished by such terms be structurally different, numerically distinct, or essentially different. For example, 'first signal' and 'second signal' may represent instances of the same signal transmitted at different times, signals containing the same core information even with some variations, or signals having different content or characteristics depending on the specific context. Similarly, 'first value' and 'second value' may represent the same magnitude measured or applied in different situations, or may represent different magnitudes. Such interpretation must be determined based on the specific technical context, function, and relationship described in the relevant parts of the specification and claims.

[0055] Furthermore, although terms such as "first," "second," etc., as used in this disclosure are used for various elements such as information, objects, actions, and sequences, they are not intended to limit such elements to a specific order. These terms may be understood merely as distinguishing one element from another. For example, a first element may be referred to as a second element, and likewise, a second element may be referred to as a first element.

[0056] Additionally, the terms 'first' and 'second' described in this disclosure may be understood to refer to identical or different elements. For example, if an element is information, the first information and the second information may both be information, and depending on the case, they may be the same information or different information.

[0057] Furthermore, the expressions 'if' and 'in case that' described in this disclosure or claims may be interpreted, depending on the context, as meaning 'when or upon,' 'in response to,' 'based on,' or 'according to,' and these expressions may be used interchangeably. In addition, other expressions having substantially the same meaning may be used as substitutes, provided that they do not impair the technical features of this disclosure.

[0058] Additionally, the term "not perform" as used in this disclosure or claims may be understood, depending on the context, to mean to omit or skip the corresponding step. Such a term may be replaced with other terms having the same or substantially similar meaning.

[0059] Additionally, the phrase "transmitting a message containing A and B" as described in this specification may be interpreted to include not only (i) cases where A and B are transmitted as a single message, but also (ii) cases where A and B are transmitted individually through multiple messages (e.g., transmitting a first message containing A and a second message containing B). This interpretation may also apply to cases where messages containing two or more items, such as A, B, and C, are transmitted together or individually.

[0060] In addition, 'transmitting a message containing A and transmitting a message containing B' can also be interpreted as transmitting a single message containing A and B.

[0061] In the specific embodiments of the present disclosure described below, terms or components included in the disclosure will be expressed in the singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the circumstances presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed in the singular form, and even if a component is expressed in the singular form, it may be composed in the plural form.

[0062] The drawings or flowcharts described below illustrate exemplary methods that may be implemented in accordance with the principles of the present disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the present disclosure. For example, although illustrated as a series of steps, the various steps of each drawing or flowchart may overlap, occur in parallel, occur in a different order, or occur multiple times. In other examples, any step may be omitted or replaced with another step.

[0063] The methods and devices proposed in the embodiments of the present disclosure below are not limited to each embodiment and may be utilized as a combination of all or part of the embodiments proposed in the disclosure. Accordingly, the embodiments of the present disclosure may be applied with some modifications within the scope that does not deviate significantly from the scope of the present disclosure, at the judgment of a person skilled in the art.

[0064] In this case, any wording mentioned in different embodiments may be used interchangeably, combined, or substituted if the concepts correspond. For example, regarding the same or corresponding concepts, even if the expression 'A' is used in one embodiment and the expression 'B' is used in another embodiment, they may be understood by interchangeably, substituted, or combined.

[0065] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used. Furthermore, where appropriate, such terms may be replaced with terms defined in the 3GPP (3rd generation partnership project) Technical Specifications (TS).

[0066] Hereinafter, the base station, as the entity performing resource allocation for terminals, may be at least one of gNode B, eNode B, Node B, BS (base station), wireless access unit, base station controller, or a node on a network. Additionally, the base station of the present disclosure may include a structure split into a central unit (CU) and a distributed unit (DU). In such a structure, the CU is responsible for the upper layer of the control and user plane, and the DU is responsible for wireless resource processing of the lower layer. The embodiments of the present disclosure can be equally applied to a 5G base station structure in which functions are separated into the CU and DU as described above.

[0067] The terminal may include a UE (user equipment), MS (mobile station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions.

[0068] In the present disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station.

[0069] In addition, while a 5th generation mobile communication system (5G, new radio, NR) and a 6th generation mobile communication system (6G) may be described below as examples, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, new advanced mobile communication systems developed after 5G and 6G may be included therein. Furthermore, the present disclosure may be applied to other communication systems (e.g., Wi-Fi systems) with some modifications made in the judgment of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0070] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0071] In describing the present disclosure below, the term "upper layer signaling" may be a signaling corresponding to at least one or a combination of at least one of MIB (master information block), SIB (system information block), SIB M (M=1, 2, ...), RRC (radio resource control), MAC (medium access control), CE (control element), NAS (non-access stratum) signaling, or application layer messages. The RRC signaling may also be referred to as L3 signaling (layer 3 signaling).

[0072] Additionally, L1 signaling may be a signaling method corresponding to at least one or a combination of at least one of the following: a physical layer channel or signaling of a PDCCH (physical downlink control channel), a DCI (downlink control information), a UE-specific DCI, a group common DCI, a common DCI, a scheduling DCI (e.g., a DCI used for the purpose of scheduling downlink or uplink data), a non-scheduling DCI (e.g., a DCI not used for the purpose of scheduling downlink or uplink data), a PUCCH (physical uplink control channel), or an UCI (uplink control information). The above L1 signaling may also be referred to as physical layer signaling.

[0073] Hereinafter, the expression in the present disclosure or claims that information can be configured from a base station may mean that, depending on the context, a terminal receives said information from a base station through physical layer signaling or upper layer signaling, and such expression may be replaced with other terms having the same or substantially similar meaning.

[0074] The operating principle of the present disclosure will be explained in detail below with reference to the attached drawings.

[0075] One of the most fundamental problems in the design and implementation of communication systems is the problem of jointly optimizing the transmitter and receiver. Joint optimization is possible when Channel State Information (CSI) is known to both the receiver and the transmitter, and the form of the solution to achieve optimization may vary depending on the transmit and receive signal models, the optimization criteria, and the channel state.

[0076] Although various studies have been conducted to solve the problem of jointly optimizing transmitters and receivers, existing studies have performed optimization in a continuous frequency domain. However, for Orthogonal Frequency Division Multiplexing (OFDM) used in 4G and 5G, optimization must be performed in a discrete frequency domain for each subcarrier, making it difficult to apply existing studies. Furthermore, Single-Carrier Frequency Division Multiple Access (SC-FDMA) used in 4G uplinks and Discrete Fourier Transform-Spread (DFT-spread) OFDM, which can be used in 5G uplinks, have signal models similar to Single Carrier (SC) signals; however, because they are methods that apply discrete precoding to OFDM and use Cyclic Prefixes (CP), their signal models are not compatible with conventional studies. In SC-FDMA or DFT-Spread OFDM, the shape of the power spectrum is determined by which complex gain value is multiplied for transmission for each discrete subcarrier. Conventional techniques, however, perform optimization over a continuous frequency f in the generalized or effective generalized Nyquist band, making it difficult to apply to SC-FDMA or DFT-Spread OFDM. In particular, conventional techniques perform optimization using the vectorized Fourier transform of the transmit / receive filter, which is a continuous-time function, but no corresponding technique is known for SC-FDMA or DFT-Spread OFDM.

[0077] The present disclosure proposes a technique for optimizing the performance of a communication system in an existing or future communication system using Discrete Fourier Transform-Spread OFDM as a waveform, by performing channel-dependent (CD) frequency-domain spectrum shaping at the transmitter and joint equalization at the receiver when channel state information can be known to the transmitter.

[0078] In DFT-spread OFDM, the power spectral density (PSD) of the transmitted signal is determined by the transmitted frequency-domain spectrum-shaping vector. In DFT-spread OFDM, conventional frequency-domain spectrum shaping (FDSS) techniques were introduced to improve performance metrics at the transmitter, such as Peak-to-Average Power Ratio (PAPR) or Cubic Metric (CM). On the other hand, the embodiments of the present disclosure perform optimizations that differ in purpose from conventional techniques in that they perform CD-FDSS at the transmitter and joint equalization at the receiver to improve performance metrics at the receiver. As an example, the Mean Square Error (MSE) of the data symbol may be used as a performance metric at the receiver.

[0079] Embodiments of the present disclosure define an effective generalized Nyquist band of an SC-FDMA or DFT-spread OFDM signal corresponding to an effective generalized Nyquist band of a continuous-time function for the joint optimization of a transmit / receive spectrum-shaping vector in the discrete frequency domain, and use this to determine a matrixized spectrum-shaping vector corresponding to a vectorized Fourier transform of a continuous-time function.

[0080] In this way, in the embodiments of the present disclosure, a transceiver using SC-FDMA or DFT-Spread OFDM can perform channel-dependent frequency-domain spectrum shaping (FDSS) by matrixing the spectrum-shaping vector according to the channel state information and then performing optimization. Unlike the channel inversion solution, the solution for the joint optimization of the transceive spectrum-shaping vector in the present disclosure is determined by the correlation matrix between the channel state information and the received noise, and unlike the zero-forcing solution, there is no noise enhancement. Furthermore, unlike the information-theoretic water-filling solution, this may be a solution that reduces the mean squared error of the transmitted data symbols rather than a solution that maximizes mutual information between the transceiver and the receiver.

[0081] For convenience of explanation, the embodiments of this disclosure have been described with reference to the linear minimum mean-squared error optimality criterion for optimizing transmit and receive FDSS vectors to minimize the mean-squared error of transmitted data symbols; however, this is merely one embodiment, and other performance indicators may be used depending on the optimality criteria set for the receiver to which this disclosure applies. For example, the embodiments of this disclosure may be applied to optimize transmit and receive FDSS vectors according to various linear optimal criteria, such as matched filter or zero-forcing optimality criteria, and various non-linear optimality criteria, such as decision-feedback optimality criteria and mutual information optimality criteria.

[0082] FIG. 1 is a block diagram showing the configuration of a DFT-spread OFDM transmitter that performs channel-dependent frequency-domain spectrum shaping (CD-FDSS) according to one embodiment of the present disclosure.

[0083] As illustrated in FIG. 1, a DFT-spread OFDM transmitter (100) according to one embodiment of the present disclosure may include a DFT spreading section (110), a circular spreading section (120), a channel-dependent frequency domain spectrum shaping section (130), a subcarrier allocation section (140), a standard CP-OFDM modulation section (150), and a transmit spectrum shaping vector generation section (160). However, this is merely an example, and the DFT-spread OFDM transmitter of the present disclosure may include other components.

[0084] Additionally, for convenience of explanation below, the discrete-time vector sequence of the DFT-spread OFDM transmitter (100) The i-th term time subscript ...is omitted and displayed. That is, The nth symbol vector If expressed as, Is It becomes a vector with symbols. Here is an even number.

[0085] The DFT diffusion unit (110) can generate a DFT-diffused symbol vector by diffusing a symbol vector containing multiple input symbols using a DFT matrix. For example, the DFT diffusion unit (110) A symbol vector containing Quadrature Amplitude Modulation (QAM) symbols is received as input, and the symbol vector can be diffused using a DFT matrix. However, this is merely an example, and the embodiments of the present disclosure may also be applied to a sequence of symbol vectors composed of symbols modulated in a different way than QAM symbols. A symbol vector of size Mx1 is received in the DFT diffusion unit (110). If is input, DFT diffused vector can be obtained.

[0086] The cyclic expansion unit (120) can generate a cyclically extended vector sequence by periodically expanding each term of the DFT-diffused symbol vector. For example, the cyclic expansion unit (120) can generate a DFT-diffused vector A cyclically expanded vector of magnitude L obtained by periodically expanding each term of You can obtain.

[0087] The channel-dependent frequency domain spectrum shaping unit (130) can generate a channel-dependent frequency domain spectrum shaping vector by multiplying each term of the cyclically expanded vector by the transmission shaping vector. For example, the channel-dependent frequency domain spectrum shaping unit (130) can generate a cyclically expanded vector Transmitting shape vector A vector formed by multiplying each component of the frequency domain spectrum A transmission shaping vector can be generated. The transmission shaping vector can be received from the transmission spectrum shaping vector generation unit (160). According to one embodiment, the transmission spectrum shaping vector generation unit (160) receives information regarding the generation of a transmission spectrum shaping vector from a receiver via a reverse channel, and based on this, matrixes an optimal channel-dependent frequency domain spectrum shaping vector and determines it according to an optimality criterion. The information regarding the generation of a transmission spectrum shaping vector may be, for example, information regarding a channel and information regarding interference and noise. According to another embodiment, the transmission spectrum shaping vector generation unit (160) may receive a transmission spectrum shaping vector determined by a receiver via a reverse channel based on information regarding a channel and information regarding interference and noise.

[0088] The subcarrier allocation unit (140) can generate a subcarrier allocated vector sequence by attaching a zero vector to a frequency-domain spectrum-shaped vector sequence and then circulating downward. For example, the subcarrier allocation unit (140) can generate a frequency-domain spectrum-shaped vector of size L. NL zero vectors After attaching, cycle downward to form a vector You can obtain.

[0089] A standard CP-OFDM modulator (150) may include an N-point IDFT unit (151), a cyclic preposition insertion unit (153), a parallel-to-serial converter (155), and a continuous-time signal generator (157). A frequency-domain vector assigned to a subcarrier by circulating downwards. is a DFT-spread OFDM symbol vector passing through the N-point IDFT section (151) in the standard CP-OFDM modulation section (150). It is converted into. Also, DFT-spread OFDM symbol vector It passes through the circulating anterior insertion part (153) ( + )time domain signal vector of size It is converted into a discrete-time signal through a parallel-to-serial converter (155). It is converted into. The DFT-spread OFDM signal, which is a continuous-time real bandpass signal, passes through the continuous-time signal generation unit (157). It is converted into. The operation of the standard CP-OFDM modulation unit (150), from the N-point IDFT unit (151) to the continuous-time signal generation unit (157), is a widely known technology in the technical field to which the embodiments of the present disclosure belong, so the description thereof will be omitted.

[0090] Hereinafter, with reference to FIGS. 2 to 5, the operation of the DFT diffusion section (110), circular expansion section (120), channel-dependent frequency domain spectrum shaping section (130), and subcarrier allocation section (140) will be described in detail. In addition, in the embodiment of FIGS. 2 to 5, the description will be made assuming that the input symbol is a QAM symbol.

[0091] FIG. 2 is a diagram illustrating the DFT-spread section of a DFT-spread OFDM transmitter that performs CD-FDSS according to one embodiment of the present disclosure.

[0092] Referring to FIG. 2, the DFT diffusion section (110) is of a size DFT matrix QAM symbol vector using Diffusion of to DFT diffused QAM symbol vector It can generate. In this case, the DFT matrix The (i, j) component of can be determined based on mathematical formula 1.

[0093] [Mathematical Formula 1]

[0094]

[0095] In Equation 1, indices i and j satisfy 1 ≤ i ≤ M and 1 ≤ j ≤ M, respectively. As shown in Fig. 2, the DFT-diffusing vector It can be generated according to mathematical formula 2.

[0096] [Mathematical Formula 2]

[0097]

[0098] FIG. 3 is a diagram illustrating a circular expansion section of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0099] Referring to FIG. 3, the cyclic expansion section (120) is a QAM symbol vector DFT-diffused vector obtained by DFT diffusion Periodically expand the length cyclic expanded vector You can generate . Here is an even number and the length in vector is length cyclic expanded vector It is located in the center of. That is, the above-mentioned cyclically expanded vector according to mathematical equation 3. of The th component and The i-th component has the same value, and this is the DFT diffused vector of It is the same as the nth component.

[0100] [Mathematical Formula 3]

[0101]

[0102] As shown in Fig. 3, the cyclically expanded vector Is line Column-cycle expansion matrix It can be generated according to mathematical formula 4 using .

[0103] [Mathematical Formula 4]

[0104]

[0105] If we substitute Equation 2 into Equation 4 here, we get the cyclic expansion matrix is given by mathematical formula 5 line Column-cycle expanded DFT matrix It can be easily seen that it can be expressed as in mathematical formula 6 using .

[0106] [Mathematical Formula 5]

[0107]

[0108] In mathematical equation 5, indices i and j satisfy 1≤i≤L and 1≤j≤M, respectively.

[0109] [Mathematical Formula 6]

[0110]

[0111] In mathematical formula 6, is a matrix It refers to the Hermitian-transposition matrix.

[0112] FIG. 4 is a diagram illustrating a channel-dependent frequency domain spectrum shaping unit and a transmission spectrum shaping vector generation unit of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0113] Referring to FIG. 4, the channel-dependent frequency-domain spectrum shaping portion (130) is a cyclically expanded vector For each component, the channel-dependent frequency-domain spectrum-shaping vector received by the transmission spectrum shaping vector generation unit (160) A frequency-domain spectrum-shaped vector formed by multiplying each component of It can generate. In other words, according to Equation 7 as illustrated in FIG. 4, the transmission spectrum shaping part (130) is a cyclically expanded vector as in Equation 3. Transmission spectrum shaping vector of the same length Hadamard product Frequency-domain spectrum shaped vector by ) Generate or shape vector A matrix with diagonal elements By pre-multiplying, the vector It may also be generated.

[0114] [Mathematical Formula 7]

[0115]

[0116] According to one embodiment, the transmission spectrum forming vector generation unit (160) receives information regarding the generation of a transmission spectrum forming vector from a receiver through a reverse channel and can determine an optimal channel-dependent frequency domain spectrum forming vector based on an optimality criterion. According to another embodiment, the transmission spectrum forming vector generation unit (160) can receive a transmission spectrum forming vector determined by a receiver through a reverse channel based on an optimality criterion, based on information regarding channels and information regarding interference and noise.

[0117] The optimality criteria of the present disclosure and the algorithm for finding the optimal transmission shape vector will be described in detail later with reference to FIGS. 9 and FIGS. 10.

[0118] FIG. 5 is a diagram illustrating a subcarrier allocation unit of a DFT-spread OFDM transmitter performing CD-FDSS according to one embodiment of the present disclosure.

[0119] Referring to FIG. 5, the subcarrier allocation unit (140) is a frequency-domain spectrum-shaped vector By assigning to subcarriers within the allocated frequency range, the vector It can generate. As illustrated in FIG. 5, according to Equation 8, the assignment to the subcarrier is the frequency domain spectrum-shaped length. vector of length The zero vector of After zero-padding with the attachment, the length created in this way Size in the vector circular down-shift matrix It can be performed by multiplying.

[0120] [Mathematical Formula 8]

[0121]

[0122] Size here In-unit downward cyclic matrix of The element can be defined by mathematical formula 9.

[0123] [Mathematical Formula 9]

[0124]

[0125] Here, The aforementioned in Fig. 1 - The size of the DFT matrix to be used in the point IDFT section (151), and mod is the modulo operation. Indices i and j satisfy the conditions 1 ≤ i ≤ N and 1 ≤ j ≤ N, respectively.

[0126] In mathematical equation 8, when the assigned subcarriers are from the (J+1)th subcarrier to the (J+M)th subcarrier, the downward cyclic matrix ( The index of ) and the amount to cycle downward It can be defined by mathematical formula 10.

[0127] [Mathematical Formula 10]

[0128]

[0129] FIG. 6 is a flowchart of a DFT-spread OFDM transmission method for performing CD-FDSS according to one embodiment of the present disclosure.

[0130] Referring to FIG. 6, in step S610, the transmitter A sequence of symbol vectors containing QAM symbols Receives as input DFT matrix QAM symbol vector sequence using The DFT-diffused symbol vector sequence obtained by spreading each term of It can generate.

[0131] In step S620, the transmitter is the DFT-spread QAM symbol vector sequence Periodically expanding each term of the length cyclically expanded vector sequence It can generate.

[0132] In step S630, the transmitter is length cyclically expanded vector sequence transmission shape vector for each term A vector sequence of channel-dependent frequency-domain spectrum shaped by multiplying It can generate. In this case, the vector is a cyclically expanded vector channel-dependent frequency-domain spectrum-shaping vector Multiplying Hadamard or shaping vector A matrix with diagonal elements It can also be generated by leading multiplication.

[0133] In step S640, the transmitter is a frequency domain spectrum-shaped vector sequence Length for each term The zero vector of After attaching, rotate downward to the vector assigned to the subcarrier It can generate. In this case, the vector is the above vector with the zero vector attached The size of In downward cyclic matrix It can be obtained by leading multiplication.

[0134] In step S650, the transmitter receives the subcarrier-assigned frequency domain vector sequence in a downward loop. A DFT-spread OFDM signal that takes as input and performs standard cyclic-prefix OFDM modulation. It can generate.

[0135] FIG. 7 is a block diagram showing the configuration of a DFT-spread OFDM receiver that receives a signal to which CD-FDSS is applied according to one embodiment of the present disclosure.

[0136] Referring to FIG. 7, a DFT-spread OFDM receiver (700) according to one embodiment of the present disclosure may include a standard CP-OFDM demodulator (710) comprising a discrete-time complex baseband signal generation (711), a serial-to-parallel conversion (713), a cyclic pre-removal (CP) (715), and an N-point DFT unit (717), a subcarrier selection unit (720), a receiving frequency-domain spectrum shaping unit (730), a spectrum folding unit (740), a DFT-depsreading unit (750), a channel state information estimation unit (760), a receiving spectrum-shaping vector generation unit (770), and a transmitting spectrum-shaping vector information transmission unit (780). However, this is merely an example, and the components of the DFT-spread OFDM receiver (700) are not limited to those described above, and other components may be included.

[0137] Continuous-time real bandpass DFT-spread OFDM signal received through the channel is a discrete-time complex baseband-equivalent signal in the discrete-time signal generator (711). It can be converted into. is the length in the serial-parallel conversion unit (713). The length is converted into a vector sequence and the CP portion is removed in the cyclic transposition removal section (715). Time-domain received vector sequence It is converted into, and is a series of frequency-domain vectors of length N in the N-point DFT section (717). It is converted into. At this time, the transmitted signal The impulse response of the channel is the length of CP A signal passing through a frequency-selective channel shorter than the product of the sample intervals It is assumed that it is received. The operation of the standard CP-OFDM demodulator (710), from the discrete-time signal generator (711) to the N-point DFT unit (717), is a widely known technology in the art to which the embodiments of the present disclosure belong, so the description thereof is omitted in this specification.

[0138] For convenience of explanation below, the k-th terms of the discrete-time vector sequences of the DFT-spread OFDM receiver (700), as in the transmitter, are shown with the time subscript k omitted.

[0139] The subcarrier selection section (720) is of length Frequency domain reception vector The subcarrier range allocated in Select the portion corresponding to the subcarriers and the length in vector It can generate. If the allocated subcarriers are from the (J+1)th subcarrier to the (J+M)th subcarrier is the identity downward cyclic matrix of mathematical formula 9 ( It can be defined by mathematical formula 11 using ).

[0140] [Mathematical Formula 11]

[0141]

[0142] Here, silver It is an identity matrix. silver It is a zero matrix. It becomes a circular up-shift matrix.

[0143] Equation 11 is the magnitude when the frequency-selective channel satisfies the above conditions regarding the impulse response length and CP length. The frequency-domain channel matrix that is the diagonal matrix of It can be expressed as in Equation 12 using . Here, the vector is length It is the frequency-domain channel response vector.

[0144] [Mathematical Formula 12]

[0145]

[0146] Here, interference and noise vectors is the covariance matrix as shown in Equation 13 It can be modeled as proper-complex Gaussian interference and noise vectors, but this is just one example, and the interference and noise vectors do not necessarily have to be Gaussian.

[0147] [Mathematical Formula 13]

[0148]

[0149] The forward channel information estimation unit (760) receives a predefined reference signal as input and a frequency-domain channel matrix and interference and noise covariance matrix It can be estimated. For example, the reference signal may be a signal formed by a spectrum forming vector that is known and agreed upon in advance between the transmitter (100) and the receiver (700). Since the operation of estimating the channel, interference, and noise covariance matrix based on the reference signal is a widely known technique in the art to which the embodiments of the present disclosure belong, the description thereof will be omitted.

[0150] The receiving frequency-domain spectrum forming portion (730) is of length Selected vector of subcarrier As in mathematical formula 14, the length In receiving spectrum-shaping vector The complex vector of Vector of the frequency-domain received spectrum formed by the Hadamard multiplication It can generate.

[0151] [Mathematical Formula 14]

[0152]

[0153] Here, the superscript * signifies a transformation to the complex conjugate, so the complex conjugate of The nth term is the reception spectrum-shaping vector of It is the complex conjugate of the i-th term.

[0154] The receiving spectrum-shaping vector generation unit (770) obtains the frequency-domain channel matrix from the forward channel information estimation unit (760). and interference and noise covariance matrix Upon receiving information, the optimal receiving frequency-domain spectrum-shaping vector can be determined based on the optimality criterion.

[0155] The spectrum folding section (740) is a receiving frequency-domain spectrum-shaped vector is central Spectrum folding based on components to length in vector It can generate. Therefore, the cyclic expansion matrix of Equation 6 Using gives a spectrum-folded vector It can be expressed as in mathematical formula 15.

[0156] [Mathematical Formula 15]

[0157]

[0158] The DFT-reverse diffusion section (750) is a spectrum-folded vector Hermite transposed DFT matrix The inversely diffused vector as in Equation 16 by leading multiplication It can generate.

[0159] [Mathematical Formula 16]

[0160]

[0161] A transmission spectrum forming vector generation information transmission unit (780) according to one embodiment is a frequency domain channel matrix and interference and noise covariance matrix Information regarding can be compressed or uncompressed and transmitted to the transmitter through a reverse channel. Additionally, according to one embodiment, the transmission spectrum shaping vector generation information transmission unit (780) can calculate the optimal transmission frequency-domain spectrum shaping vector using the optimal reception frequency-domain spectrum shaping vector received from the reception spectrum shaping vector generation unit (770) and the optimal transmission frequency-domain spectrum shaping vector, and transmit it to the transmitter through a reverse channel after compressing or uncompressing it. Furthermore, the transmission spectrum shaping vector generation information transmission unit (780) can provide information that helps the transmitter generate the optimal transmission spectrum shaping vector in various other ways.

[0162] Since the technique of compressing or decompressing channel state information, etc., and feeding it back through a reverse channel is a widely known technique in the technical field to which the embodiments of the present disclosure belong, its description will be omitted in the present disclosure.

[0163] FIG. 8 is a flowchart of a DFT-spread OFDM receiving method according to one embodiment of the present disclosure.

[0164] Referring to FIG. 8, in step S810, the receiver receives a continuous-time real bandpass signal that has passed through a frequency-selective channel. Takes as input and performs standard CP-OFDM demodulation to obtain a sequence of frequency-domain vectors It can generate.

[0165] In step S820, the receiver is length Frequency domain received vector sequence Select the portion corresponding to the subcarrier of the assigned frequency range, and the length A series of vectors It can generate.

[0166] In step S830, the receiver [receives] the subcarrier selected vector sequence Received spectrum-shaping vector for each term The complex vector of A vector sequence of the received frequency-domain spectrum formed by the Hadamard multiplication It can generate.

[0167] In step S840, the receiver is a vector sequence of the received frequency-domain spectrum-shaped stream Spectral folding of each term length vector sequence It can generate.

[0168] In step S850, the receiver receives the spectrum-folded vector sequence The DFT matrix with the Hermite transpose for each term The vector sequence inversely spread by leading multiplication It can generate.

[0169] Mean Squared Error (MSE) may be used as a performance indicator to find the optimal transmit and receive frequency-domain spectrum-shaping vectors to be used in a DFT-spread OFDM transmitter and receiver according to one embodiment of the present disclosure, and the Mean Squared Error may be defined as in Equation 17. However, this is merely an example, and the optimized spectrum-shaping vectors considered in the present disclosure are not limited to spectrum-shaping vectors that minimize the Mean Squared Error.

[0170] [Mathematical Formula 17]

[0171]

[0172] In mathematical formula 17 is the square norm of the vector, and if the frequency-selective channel satisfies the conditions regarding the impulse response length and CP length, the MSE value is It is irrelevant to.

[0173] The optimal transmit spectrum-shaping vector that jointly minimizes the MSE defined above and reception spectrum-shaping vector To find , an optimization problem such as mathematical formula 18 can be constructed.

[0174] [Mathematical Formula 18]

[0175]

[0176] Constraint in Equation 18 It can be defined to impose constraints on the average power of the transmitted signal.

[0177] The objective function of this optimization problem It can be represented by defining a matrixized spectrum-shaping vector, given length The spectrum-shaping vector of If so, it is a matrixized spectrum-shaping vector is a QAM symbol vector The length of When It consists of column vectors and The i-th column vector silver of The third, ( )th, ( It is a vector composed of the )th, ..., components. Here and in 1 The band up to can be defined as the effective generalized Nyquist band of a DFT-spread OFDM signal. Therefore, the maximum effective bandwidth to which power is allocated is This becomes. It can be described as a discrete-frequency offset or index.

[0178] Equation 19 is the transmitted or received spectrum-shaping vector Given, the length You can open the shaping vector matrix It shows how to matrixize. That is, the shaping vector Each element of the matrix one by one in order It can be assigned as a row element.

[0179] [Mathematical Formula 19]

[0180]

[0181] in other words

[0182] Therefore, vector of the nth element and matrix The (i, m)th element of The relationship with is given as in mathematical formula 20.

[0183] [Mathematical Formula 20]

[0184]

[0185] In mathematical formula 20, column index silver Satisfying and row index Is Since it satisfies, this If it is not an integer multiple, the length Human molding vector The number of columns matrix When converted, it can be converted into an irregular matrix where the lengths of each column are not equal.

[0186] Mathematical formula 21 is a forming vector The length of is 6, that is =6 and QAM symbol vector That is, the length is 4 Forming vector in the case Wedge matrix , and of The first column It is giving examples of...

[0187] [Mathematical Formula 21]

[0188]

[0189] As exemplified in Equation 21, the spectrum-shaping matrix Is This above If it is not a multiple of The first column The length of It may vary depending on. As such, the present disclosure does not necessarily require that existing vectors be represented as regular matrices, i.e., rectangular matrices, when expressed in matrix form. class It is significantly different in that it can be matrixed into a non-normal matrix depending on the relationship.

[0190] Meanwhile, interference and noise vectors of Equation 13 If the interference has data-like characteristics, then the interference and noise covariance matrix is the diagonal element and in the diagonal element Only the component dropped down and / or to the right by a multiple of may not be zero. That is, the interference and noise vectors of Equation 13 If the interference has data-similar characteristics, the covariance matrix It becomes a sparse matrix of a special shape described. This case occurs in the case of multiple access that allows multi-layer transmission in DFT-spread OFDM.

[0191] Covariance matrix similar to the method of constructing the spectrum-shaping matrix second Matrices that are matrix-valued power spectral densities It can be expressed as, where is a square matrix, and its (1,1) element is It is the (m,m) component of the matrix, and the remaining components are as above Down and / or to the right of the (m,m) element of the matrix It consists of components separated by multiples of .

[0192] Mathematical formula 22 is Igo In the case of The (i,j) component of When let, the matrix-value power spectral density is It is giving examples of...

[0193] [Mathematical Formula 22]

[0194]

[0195] As exemplified in Equation 22, the matrix-value power spectral density is This above If it is not a multiple of The i-th matrix The size of It may vary depending on. As such, the present invention is significantly different from any existing method in the method of representing the existing interference and noise covariance matrix as several sub-matrices.

[0196] The objective function of mathematical equation 18 To express this in terms of the above spectrum-shaping matrix and matrix-value power spectral density, the Hadamard product in Equation 12 is of length as in Equation 23 in vector It can be defined as.

[0197] [Mathematical Formula 23]

[0198]

[0199] Transmission Spectrum-Shaping Vector Spectrum-shaping matrix of of The nth column vector It is called, and the received spectrum-shaping vector Spectrum-shaping matrix of of The nth column vector It is called, and the transmission spectrum-shaping vector that has passed through the channel. Spectrum-shaping matrix of of The nth column vector If so, the objective function of mathematical equation 18 When QAM symbols are modeled as zero-mean unit-variance uncorrelated random variables, it can be expressed as Equation 24.

[0200] [Mathematical Formula 24]

[0201]

[0202] Here, the matrix It is given as in mathematical formula 25.

[0203] [Mathematical Formula 25]

[0204]

[0205] Likewise, using the column vectors of the transmit spectrum-shaping matrix, the average power limiting condition of Equation 18 Representing it again, it becomes the same as mathematical formula 26.

[0206] [Mathematical Formula 26]

[0207]

[0208] Here silver The energy of the i-th column vector is defined as in Equation 27.

[0209] [Mathematical Formula 27]

[0210]

[0211] When solving the optimization problem by substituting Equations 24, 26, and 27 into Equation 18, the optimal transmit spectrum-shaping matrix and optimal receive spectrum-shaping matrix ...can be obtained. To this end, it is necessary to find the solution by transforming the joint optimization problem of the transmit spectrum-shaping vector and the receive spectrum-shaping vector into a nested optimization problem. First, in the inner optimization problem, the matrixized optimal receive spectrum-shaping vector nth column vector In calculating, of the matrixed optimal transmit spectrum-shaping vector The i-th column vector Assuming this is given, the linear minimum mean squared error (LMMSE) solution is obtained. The inner optimization problem becomes an unconstrained optimization problem, effectively generalizing the Nyquist band angle discrete-frequency offset or index. When solving the vector-matrix quadratic equation, the point where the gradient vector becomes zero is obtained as the optimal solution as shown in Equation 28.

[0212] [Mathematical Formula 28]

[0213]

[0214] In mathematical formula 28, the numerator's is the frequency-domain channel response vector of Equation 12 When matrixed in the same way as the matrixing of the spectrum-shaping vector nth column vector It was converted into a square matrix as shown in mathematical formula 29.

[0215] [Mathematical Formula 29]

[0216]

[0217] Receivers typically use pilot or reference symbols to generate frequency-domain channel response vectors Since it can be estimated, the receiver matrixes this estimate and each The i-th column vector Using mathematical formula 28 You can obtain a vector.

[0218] FIG. 9 shows the optimal reception spectrum-shaping vector of a DFT-spread OFDM receiver according to one embodiment of the present disclosure. This is a flowchart to explain how to find it.

[0219] A receiving spectrum-shaping vector generation unit of a DFT-spread OFDM receiver according to one embodiment generates an optimal receiving spectrum-shaping vector in the order of FIG. 9. It can generate. A method for a DFT-spread OFDM receiver according to one embodiment of the present disclosure to find an optimal received spectrum-shaping vector can be performed using Equations 20, 22, 28, and 29.

[0220] Referring to FIG. 9, in step S910, the receiver obtains an optimal transmit spectrum-shaping vector through a frequency-selective channel. and interference and noise matrix It is possible to generate an estimate of.

[0221] In step S920, the receiver is a vector Matrix-ize each column vector Calculate and the interference and noise matrices From matrix-value power spectrum density column It can generate.

[0222] In step S930, the receiver is a column vector and matrix-value power spectral density matrixed optimal reception spectrum-shaping vector from The i-th column vector It can generate. The receiver is a column vector based on the aforementioned mathematical formula 28. and matrix-value power spectral density Using It can generate.

[0223] In step S940, the receiver [determines] all discrete-frequency offsets or indices from step S910 to S930 Optimal receive spectrum-shaping matrix obtained by performing on From, the length is obtained by performing the method for matrixizing the spectrum-shaping vector (Equation 20) in reverse order. Optimal reception spectrum-shaping vector It can generate.

[0224] Matrixed Optimal Receive Spectrum-Shaping Vector By substituting each column vector of into Equation 22, the outer optimization problem is only In terms of expression, the optimized mean squared error at the receiver can be determined as shown in mathematical formula 30.

[0225] [Mathematical Formula 30]

[0226]

[0227] The receiver minimizes the optimized mean squared error, Equation 30, under the constraints given by Equations 26 and 27. ...can be found. To do this The energy density function of By defining , mathematical formula 30 can be expressed as mathematical formula 31.

[0228] [Mathematical Formula 31]

[0229]

[0230] To simplify the denominator in Equation 31, as in Equation 32 A matrix can be defined.

[0231] [Mathematical Formula 32]

[0232]

[0233] To perform optimization, the part enclosed in square brackets in the denominator of Equation 31 is defined by Equation 32 It must be the maximum value of the matrix's Rayleigh quotient. That is, Equation 33 is It shows that the matrix provides tight upper and lower bounds for the part enclosed in square brackets.

[0234] [Mathematical Formula 33]

[0235]

[0236] Here Is It is the maximum value of the matrix's eigenvalues, and Is It is the minimum value of the matrix's eigenvalues. Therefore, the matrixized optimal transmit spectrum-shaping vector nth column vector Is The eigenvector corresponding to the maximum value of the matrix It must be a non-zero multiple of and must be given as in Equation 34 to satisfy the definition of Equation 27.

[0237] [Mathematical Formula 34]

[0238]

[0239] Here Igo is not affected by the minimized mean squared error even if it is chosen as an arbitrary function. For example, It may also be optimized to reduce PAPR, a performance metric other than Mean Squared Error. However, this is just one example, This is not limited to the aforementioned examples. When substituting Equation 34 into Equation 30, It can be simplified to mathematical equation 35.

[0240] [Mathematical Formula 35]

[0241]

[0242] The optimal energy distribution solution that minimizes the sum of mathematical equation 35 Find the constraints as Equation 26. The optimal energy distribution method for this optimization problem can be named the Weighted Water Filling Procedure, which is Equation 36.

[0243] [Mathematical Formula 36]

[0244]

[0245] In mathematical equation 36, the function is the ReLU (Rectified Linear Unit) function, and is positive Is It is the unique solution to mathematical equation 37, which is an equation for .

[0246] [Mathematical Formula 37]

[0247]

[0248] FIG. 10 is an optimal transmit spectrum-shaping vector of a DFT-spread OFDM transmitter according to one embodiment of the present disclosure. This is a flowchart to explain how to find it.

[0249] Optimal transmission spectrum-shaping vector It can be calculated in the transmission spectrum shaping vector generation unit (160) of the transmitter according to the order of FIG. 10, and after being calculated in the transmission spectrum shaping vector generation information transmission unit (780) of the receiver, it can be compressed or uncompressed and transmitted to the transmission spectrum shaping vector generation unit (160) through the reverse channel.

[0250] A method for finding the optimal transmit spectrum-shaping vector of a DFT-spread OFDM transmitter according to one embodiment of the present disclosure can be performed using Equations 34, 35, 36, and 37.

[0251] Referring to FIG. 10, in step S1010, the transmitter The eigenvector corresponding to the maximum value of the matrix All discrete-frequency offsets or indices of the effective generalized Nyquist band Can be created for. A matrix can be defined as in Equation 32.

[0252] In step S1020, the transmitter distributes the optimal energy It can generate the optimal energy distribution solution. The optimal energy distribution solution can be generated using mathematical equations 36 and 37. The order of steps S1010 and S1020 can be changed.

[0253] In step S1030, the transmitter generates in steps S1010 and S1020 class Substituting into Equation 31 yields the matrixized optimal transmit spectrum-shaping vector The i-th column vector It can generate.

[0254] In step S1040, the transmitter uses the optimal transmit spectrum-shaping matrix obtained in step S1030 From, by inversely utilizing the relationship in Equation 20 for matrixing the spectrum-shaping vector, the length Optimal transmission spectrum-shaping vector It can generate.

[0255] FIG. 11 is a drawing for explaining a DFT-spread OFDM communication system according to one embodiment of the present disclosure.

[0256] Referring to FIG. 11, the DFT-spread OFDM communication system (1100) may include the DFT-spread OFDM transmitter described above with reference to FIG. 1 and the DFT-spread OFDM receiver described above with reference to FIG. 7.

[0257] The description of the DFT spreading section (110), circular spreading section (120), channel-dependent frequency domain spectrum shaping section (130), subcarrier allocation section (140), and standard CP-OFDM modulation section (150) of the DFT-spread OFDM transmitter shown in FIG. 11 is the same as described above in FIG. 1. Additionally, the description of the standard CP-OFDM demodulation section (710), subcarrier selection section (720), receiving frequency-domain spectrum shaping section (730), spectrum folding section (740), DFT inverse spreading section (750), forward channel information estimation section (760), receiving spectrum shaping vector generation section (770), and transmitting spectrum shaping vector generation information transmission section (780) of the DFT-spread OFDM receiver shown in FIG. 11 is the same as described above in FIG. 7.

[0258] Referring to FIG. 11, the receiver may transmit information regarding the generation of a transmission spectrum shaping vector or the transmission spectrum shaping vector to the transmitter through the reverse channel. In the present disclosure, the forward channel refers to the channel in the direction in which data symbols are transmitted, and the reverse channel refers to the channel in the direction in which information regarding the generation of a transmission spectrum shaping vector is transmitted. When CD-FDSS is used in the uplink, the forward channel is the uplink and the reverse channel is the downlink. When CD-FDSS is used in the downlink, the forward channel is the downlink and the reverse channel is the uplink.

[0259] For example, when CD-FDSS is used in the uplink, the transmitting terminal can receive information regarding the generation of the transmit spectrum shaping vector or the transmit spectrum shaping vector from the receiving base station. According to another example, when CD-FDSS is used in the downlink, the transmitting base station can receive information regarding the generation of the transmit spectrum shaping vector or the transmit spectrum shaping vector from the receiving terminal.

[0260] FIG. 12 is a diagram illustrating a method for transmitting and receiving a DFT-spread OFDM signal with an optimal spectrum shaping vector applied in a transmitter and a receiver according to one embodiment of the present disclosure.

[0261] Referring to FIG. 12, in step S1210, the receiver (700) can obtain information about the channel and information about interference-noise. For example, the receiver (700) can estimate the channel using a reference signal transmitted from the transmitter (100) and obtain information about the channel and information about interference-noise based on the estimated channel.

[0262] In step S1220, the receiver (700) can transmit information regarding the generation of the transmission spectrum shaping vector to the transmitter (100).

[0263] Information regarding the generation of a transmission spectrum shaping vector according to one embodiment may include information regarding a channel and information regarding interference-noise. The information regarding the channel may be values ​​such as a matrix or vector representing channel characteristics estimated based on a reference signal, or it may be an indicator or index representing a predefined channel state between the transmitter (100) and the receiver (700). When an indicator or index representing a predefined channel state is used, the size of the information transmitted from the receiver (700) to the transmitter (100) is reduced, thereby reducing the overhead caused by feedback. The information regarding interference-noise may also be values ​​such as a matrix or vector representing interference and noise, or it may be an indicator or index representing interference-noise predefined between the transmitter (100) and the receiver (700).

[0264] Information regarding the generation of a transmission spectrum forming vector according to another embodiment may include a channel-dependent transmission spectrum forming vector calculated at the receiver (700). The receiver (700) may determine a channel-dependent reception spectrum forming vector based on optimality criteria based on channel and interference noise, and calculate a channel-dependent transmission spectrum forming vector based thereon. According to yet another embodiment, information regarding the generation of a transmission spectrum forming vector may include an indicator or index corresponding to a channel-dependent transmission spectrum forming vector calculated at the receiver (700) based on channel information, among indicators or indices representing predefined channel-dependent transmission spectrum forming vectors between the transmitter (100) and the receiver (700).

[0265] In step S1230, the transmitter (100) can determine a channel-dependent transmission spectrum shaping vector based on information regarding the generation of the transmission spectrum shaping vector.

[0266] In step S1240, the transmitter (100) can transmit a DFT-spread OFDM signal including at least one symbol based on a determined channel-dependent-transmit spectrum shaping vector.

[0267] Meanwhile, the embodiments of the present disclosure may also be applied to MIMO (Multiple-Input Multiple-Output) transmitters and receivers.

[0268] The optimal channel-dependent transmit / receive spectrum shaping vector according to the present disclosure can exhibit higher performance than a transceiver that does not perform channel-dependent transmit / receive spectrum shaping by selecting subcarriers with higher signal-to-noise ratios in a frequency-selective channel environment. Furthermore, the optimal channel-dependent transmit / receive spectrum shaping vector according to the present disclosure can achieve higher performance than a transceiver that does not perform channel-dependent transmit / receive spectrum shaping by finding a subspace with a higher signal-to-interference-plus-noise ratio (SINR) and appropriately allocating transmit power or energy in the presence of data-like interference.

[0269] FIG. 13 is a block diagram of a transmitter according to one embodiment of the present disclosure.

[0270] The transmitter (1300) is an electronic device capable of wireless communication and can perform wireless communication with other electronic devices. The transmitter (1300) can perform the operation of the aforementioned DFT-spread OFDM transmitter.

[0271] Referring to FIG. 13, the transmitter (1300) may include at least one transceiver (1301) (hereinafter, transceiver), at least one processor (1302) (hereinafter, processor), and at least one memory (1303) (hereinafter, memory). According to at least one or a combination thereof of methods corresponding to embodiments of the present disclosure, the transceiver (1301), processor (1302), and memory (1303) of the transmitter (1300) may be operated. However, the components of the transmitter (1300) are not limited to the examples of components shown in FIG. 13. In other embodiments, the transmitter (1300) may include additional components in addition to the aforementioned components, or some components may be omitted. Also, in some embodiments, any combination of the transceiver (1301), processor (1302), or memory (1303) may be integrated into a single component.

[0272] The transceiver (1301) may be a basic communication circuit or communication circuitry that enables the transmitter (1300) to perform wireless communication with a node or entity of the network. For example, the transceiver (1301) may enable the transmitter (1300) to transmit and receive signals via wireless communication with a node or entity of the network. For example, the transceiver (1301) may support at least one of various cellular wireless communication technologies including 3G (3rd generation), 4G (4th generation) LTE (long-term evolution), 5G (5th generation) NR (new radio), 6G (6th generation), etc., and the various cellular wireless communication technologies supported by the transceiver (1301) may include all subsequent generations of wireless communication.

[0273] According to one embodiment, the transmitter (1300) may include a plurality of transceivers, and for example, when supporting EN-DC (E-UTRA (evolved-universal terrestrial radio access) - NR dual connectivity), it may include a first transceiver supporting 4G LTE wireless communication and a second transceiver supporting 5G NR wireless communication. According to another embodiment, when the transmitter (1300) supports NR-DC (NR Dual Connectivity), the transmitter (1300) may include a plurality of transceivers supporting 5G NR wireless communication. According to another embodiment, if the transmitter (1300) supports short-range wireless communication, the transmitter (1300) may separately include a transceiver that supports at least one of a family of wireless communication protocol standards such as those defined by Bluetooth®, wireless LAN or WLAN (wireless local area network) network (including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba and 802.11be).

[0274] According to one embodiment, the transceiver (1301) may include various circuit structures used to transmit and receive signals to and from a network node or entity via a wireless channel. The signals may include control information and data. For example, the transceiver (1301) may be configured to include a radio frequency (RF) transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. The transceiver (1301) may output the signal received via the wireless channel to a processor (1302) and transmit the signal output from the processor (1302) via the wireless channel.

[0275] A processor (1302) may control the overall operation of a transmitter (1300) according to an embodiment of the present disclosure. The processor (1302) may be implemented as one or more IC (integrated circuit (or circuitry)) chips and may perform various data processing operations. The processor (1302) may include at least one electrical circuit and may execute instructions (or programs, code, data, etc.) stored in memory (1303) individually, collectively, or in any combination. Additionally, the processor (1302) may include a single-core processor or a multi-core processor, and in a specific implementation, may be composed of a processor assembly including a plurality of processing circuits.

[0276] The processor (1302) is electrically, operatively, or communicatively coupled to the transceiver (1301) so as to control the transceiver (1301).

[0277] The processor (1302) may include at least one processor (or, processing circuitry), and at least one processor may perform the following operations individually, collectively, or in any combination. For example, the processor (1302) may include a communication processor (CP) that controls communication operations and an application processor (AP) that controls the execution of an upper layer (e.g., an application layer). In a specific embodiment, at least one part of the processor (1302) may be included in one chip, and another part of the processor (1302) may be included in a separate chip. Alternatively, at least one processor may be included in other components, e.g., a transceiver (1301) or a memory (1303).

[0278] The processor (1302) may perform, cause, or control the operation of a DFT-spread OFDM transmitter to perform at least one of the methods according to embodiments of the present disclosure or a combination thereof. To this end, the processor (1302) may control other components of the transmitter (1300) to perform various operations by executing computer programs, code, or instructions stored in memory (1303).

[0279] Memory (1303) is a hardware storage device capable of storing information temporarily or permanently and may include one or more storage media. For example, memory (1303) may include a memory assembly comprising one or more storage media. For example, the one or more storage media may include a hard drive, flash memory, permanent memory such as ROM (read-only memory), semipermanent memory such as RAM (random access memory), cache memory, or any combination thereof.

[0280] The memory (1303) can be electrically, operatively, or communically coupled with the processor (1302) and can be accessed by the processor (1302).

[0281] A computer program, code, or instruction that can be executed by a processor (1302) may be stored in the memory (1303). According to one embodiment, the computer program, code, or instruction that can be executed by the processor (1302) may be stored in a single memory device or may be separated and distributed across two or more memory devices. The processor (1302) may perform various functions according to the embodiments of the present disclosure by executing the instruction stored in the memory (1303).

[0282] According to one embodiment of the present disclosure, the operation of the transmitter (1300) may be caused to be performed based on at least one processor (or processing circuit) configured to perform the features of the present disclosure individually, collectively, or in any combination based on the execution of instructions (or computer program or code) stored in memory (1303), based on processing circuitry not configured to execute instructions, and / or based on components of a processing circuitry not configured to execute instructions.

[0283] FIG. 14 is a block diagram of a receiver according to one embodiment of the present disclosure.

[0284] The receiver (1400) is an electronic device capable of wireless communication and can perform wireless communication with other electronic devices. The receiver (1400) can perform the operation of the aforementioned DFT-spread OFDM receiver.

[0285] Referring to FIG. 14, a receiver (1400) may include at least one transceiver (1401) (hereinafter, transceiver), at least one processor (1402) (hereinafter, processor), and at least one memory (1403) (hereinafter, memory). According to at least one or a combination thereof of methods corresponding to embodiments of the present disclosure, the transceiver (1401), processor (1402), and memory (1403) of the receiver (1400) may be operated. However, the components of the receiver (1400) are not limited to the examples of components shown in FIG. 14. In other embodiments, the receiver (1400) may include additional components in addition to the aforementioned components, or some components may be omitted. Also, in some embodiments, any combination of the transceiver (1401), processor (1402), or memory (1403) may be integrated into a single component.

[0286] A transceiver (1401) may be a communication circuit or communication circuitry that enables a receiver (1400) to perform wireless communication with a node or entity of a network. For example, the transceiver (1401) may enable the receiver (1400) to transmit and receive signals via wireless communication with another network entity. For example, the transceiver (1401) may support various cellular wireless communication technologies including 3G (3rd generation), 4G (4th generation) LTE (long-term evolution), 5G (5th generation) NR (new radio), 6G (6th generation), etc., and the various cellular wireless communication technologies supported by the transceiver (1401) may include all subsequent generations of wireless communication. According to one embodiment, the transceiver (1401) may include various circuit structures used to transmit and receive signals to and from a terminal via a wireless channel. The signals may include control information and data. For example, the transceiver (1401) may be configured to include an RF (radio frequency) transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. The transceiver (1401) may output the signal received through a wireless channel to a processor (1402) and transmit the signal output from the processor (1402) through a wireless channel.

[0287] A processor (1402) may control the overall operation of a receiver (1400) according to an embodiment of the present disclosure. The processor (1402) may be implemented as one or more IC (integrated circuit or circuitry) chips and may perform various data processing operations. The processor (1402) may include at least one electrical circuit and may execute instructions (or programs, code, data, etc.) stored in memory (1403) individually, collectively, or in any combination. Additionally, the processor (1402) may include a single-core processor or a multi-core processor, and in a specific implementation, may be composed of a processor assembly including a plurality of processing circuits.

[0288] The processor (1402) is electrically, operatively, or communicatively coupled to the transceiver (1401) so as to control the transceiver (1401).

[0289] The processor (1402) may include at least one processor (or processor circuitry), and at least one processor may perform the following operations individually, collectively, or in any combination. In a particular embodiment, at least one part of the processor (1402) may be included in one chip, and another part of the processor (1402) may be included in a separate chip. Alternatively, at least one processor may be included in other components, such as a transceiver (1401) or memory (1403).

[0290] The processor (1402) may perform, cause, or control the operation of a DFT-spread OFDM receiver to perform at least one of the methods according to the embodiments of the present disclosure or a combination thereof. To this end, the processor (1402) may control other components of the receiver (1400) to perform various operations by executing computer programs, code, and instructions stored in memory (1403).

[0291] Memory (1403) is a hardware storage device capable of storing information temporarily or permanently and may include one or more storage media. For example, memory (1403) may include a memory assembly comprising one or more storage media. For example, the one or more storage media may include a hard drive, flash memory, permanent memory such as ROM (read-only memory), semi-permanent memory such as RAM (random access memory), cache memory, or any combination thereof.

[0292] The memory (1403) can be electrically, operatively, or communically coupled with the processor (1402) and can be accessed by the processor (1402).

[0293] A computer program, code, or instruction that can be executed by a processor (1402) may be stored in the memory (1403). According to one embodiment, the computer program, code, or instruction that can be executed by the processor (1402) may be stored in a single memory device or may be separated and distributed among two or more memory devices. The processor (1402) may perform various functions according to the embodiments of the present disclosure by executing the instruction stored in the memory (1403).

[0294] According to one embodiment of the present disclosure, the operation of the receiver (1400) may be caused to be performed based on at least one processor (or processing circuit) configured to perform the features of the present disclosure individually, collectively, or in any combination based on the execution of instructions (or computer program or code) stored in memory (1403), based on processing circuitry not configured to execute instructions, and / or based on components of a processing circuitry not configured to execute instructions.

[0295] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory storage medium' simply means that it is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily. For example, a 'non-transitory storage medium' may include a buffer in which data is stored temporarily.

[0296] According to one embodiment, the method according to the various embodiments disclosed herein may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0297] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. In a Discrete Fourier Transform (DFT)-spread Orthogonal Frequency Division Multiplexing (OFDM) transmitter in a wireless communication system, At least one transmitting and receiving unit; At least one processor communically coupled to the above at least one transmitting and receiving unit; and It includes a memory that is coupled to communicate with at least one processor and stores one or more instructions, and When the above one or more instructions are executed individually or collectively by the above at least one processor, the DFT-spread OFDM transmitter: Receive information regarding the generation of a transmission spectrum shaping vector based on the channel between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver from the DFT-spread OFDM receiver, and Based on the received information above, a channel-dependent transmission spectrum shaping vector is determined, and Based on the channel-dependent-transmit spectrum shaping vector determined above, a DFT-spread-OFDM signal including at least one symbol is generated, and The generated DFT-spread-OFDM signal is transmitted to the receiver, and A DFT-spread OFDM transmitter in which the above channel-dependent-transmit spectrum shaping vector is determined such that LMMSE (linear minimum mean square error) is minimized based on information regarding the channel and information regarding interference-noise when an LMMSE optimality criterion is set.

2. In paragraph 1, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM transmitter additionally: A cyclically expanded vector is generated by periodically expanding a DFT-diffused symbol vector containing at least one of the above symbols, and A frequency-domain spectrum-shaped vector is generated based on the above-mentioned cyclically expanded vector and the above-mentioned channel-dependent-transmission spectrum-shaped vector, and Assign the above frequency-domain spectrum-shaped vector to a subcarrier of the assigned frequency range, A DFT-spread OFDM transmitter that generates the DFT-spread OFDM signal based on a vector assigned to the above subcarrier.

3. In paragraph 2, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM transmitter additionally: Based on the above LMMSE optimality criteria, The positive number that is the unique solution of Using, the optimal energy distribution solution Acquire, The maximum value of the eigenvalues ​​of the matrix defined as class The eigenvector corresponding to and a function optimized to reduce PAPR Using vector Decide on, having the nth column According to mathematical formula 1, the length Vector created with ( ) is determined as the above channel-dependent-transmit spectrum shaping vector, and The above mathematical formula 1 is , , is, is a matrix representing the above channel, and is a matrix representing the above interference-noise, and is the length of the above-mentioned cyclically expanded vector, and A DFT-spread OFDM transmitter, which is the number of at least one symbol mentioned above.

4. In paragraph 1, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM transmitter additionally: When a linear zero-forcing optimality criterion is set, the noise indicated by the information regarding the interference-noise is approximated to be small to determine the optimal channel-dependent-transmit spectrum shaping vector, and A DFT-spread OFDM transmitter that determines an optimal channel-dependent transmission spectrum shaping vector by approximating the interference indicated by the interference-noise information to be small when a linear matched filter optimality criterion is set.

5. In paragraph 1, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM transmitter additionally: When a decision-feedback optimality criterion is established, an optimal channel-dependent-transmit spectrum shaping vector satisfying the decision-feedback optimality criterion is determined based on information regarding the channel and information regarding the interference-noise, and A DFT-spread OFDM transmitter that determines an optimal channel-dependent transmission spectrum shaping vector satisfying the mutual information optimality criterion based on information regarding the channel and information regarding the interference-noise when the mutual information optimality criterion is established.

6. In paragraph 1, the information regarding the generation of the transmission spectrum shaping vector is, or including information regarding the above channel and information regarding the above interference-noise A DFT-spread OFDM transmitter comprising a channel-dependent transmit spectrum forming vector calculated based on a channel-dependent receive spectrum forming vector determined in the DFT-spread OFDM receiver.

7. In a Discrete Fourier Transform (DFT)-spread Orthogonal Frequency Division Multiplexing (OFDM) receiver in a wireless communication system, At least one transmitting and receiving unit; At least one processor communically coupled to the above at least one transmitting and receiving unit; and It includes a memory that is coupled to communicate with at least one processor and stores one or more instructions, and When the above one or more instructions are executed individually or collectively by the above at least one processor, the DFT-spread OFDM receiver: Determining information regarding the channel between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver and information regarding interference-noise, When the LMMSE (linear minimum mean square error) optimality criterion is set, a channel-dependent reception spectrum shaping vector is determined to minimize LMMSE based on information regarding the channel and information regarding interference-noise, and Information regarding the generation of a channel-dependent transmit spectrum forming vector corresponding to the channel-dependent receive spectrum forming vector is transmitted to the DFT-spread OFDM transmitter, and A DFT-spread OFDM receiver in which the channel-dependent-transmit spectrum shaping vector is determined in the DFT-spread OFDM transmitter based on information regarding the generation of the above channel-dependent-transmit spectrum shaping vector.

8. In paragraph 7, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM receiver additionally: A frequency-domain received vector is obtained from a DFT-spread OFDM signal received from the above DFT-spread OFDM transmitter, and Select a vector corresponding to the assigned subcarrier range in the above frequency domain reception vector, and A frequency-domain spectrum-shaped vector is generated based on the selected vector and the channel-dependent received spectrum-shaped vector, and Determine the spectrum-folded vector from the above frequency-domain spectrum-shaped vector, and A DFT inversely diffusion vector is generated based on the above spectrum-folded vector, and A DFT-spread OFDM receiver that determines at least one symbol from the above DFT despread vector.

9. In paragraph 8, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM receiver additionally: Based on the above LMMSE optimality criteria, Transmission spectrum-shaping vector passing through the channel determined by ( ) according to Equation 1, the spectrum-shaping matrix The m-th column vector of ( Create with ), The above mathematical formula 1 is , , is, A vector defined as ( )cast having the nth column Based on mathematical formula 2, the length Vector created with ( To generate ) as the optimal reception spectrum-shaping vector, and The above mathematical formula 2 is is, is a matrix representing the above channel, and is a matrix representing the above interference-noise, and is the length of the above-mentioned cyclically expanded vector, and is the number of at least one symbol mentioned above, and is length It is the frequency domain channel response vector, and DFT-spread OFDM receiver.

10. In paragraph 7, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM receiver additionally: When a linear zero-forcing optimality criterion is set, the noise indicated by the information regarding the interference-noise is approximated to be small to determine the optimal channel-dependent received spectrum shaping vector, and A DFT-spread OFDM receiver that determines an optimal channel-dependent reception spectrum shaping vector by approximating the interference indicated by the information regarding the interference-noise to be small when a linear matched filter optimality criterion is set.

11. In paragraph 7, when the one or more instructions are executed individually or in combination by the at least one processor, the DFT-spread OFDM receiver additionally: When a decision-feedback optimality criterion is established, an optimal channel-dependent received spectrum shaping vector satisfying the decision-feedback optimality criterion is determined based on information regarding the channel and information regarding the interference-noise, and A DFT-spread OFDM receiver that determines an optimal channel-dependent reception spectrum shaping vector satisfying the mutual information optimality criterion based on information regarding the channel and information regarding the interference-noise when the mutual information optimality criterion is set.

12. In paragraph 7, the information regarding the generation of the transmission spectrum shaping vector is, or including information regarding the above channel and information regarding the above interference-noise A DFT-spread OFDM receiver comprising a channel-dependent transmit spectrum forming vector calculated based on the above channel-dependent receive spectrum forming vector.

13. A method performed by a Discrete Fourier Transform (DFT)-spread Orthogonal Frequency Division Multiplexing (OFDM) transmitter in a wireless communication system, A step of receiving information regarding the generation of a transmission spectrum shaping vector based on the channel between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver from a DFT-spread OFDM receiver; A step of determining a channel-dependent transmission spectrum shaping vector based on the received information above; A step of generating a DFT-spread-OFDM signal including at least one symbol based on the channel-dependent-transmit spectrum shaping vector determined above; and The method includes the step of transmitting the generated DFT-spread-OFDM signal to the receiver, A method in which the above channel-dependent-transmit spectrum shaping vector is determined such that the LMMSE (linear minimum mean square error) is minimized based on information about the channel and information about interference-noise, when an LMMSE optimality criterion is set.

14. In Paragraph 13, The method further includes the step of periodically expanding a DFT-diffused symbol vector containing at least one symbol to generate a cyclically expanded vector. The step of generating the above DFT-spread-OFDM signal is, A step of generating a frequency-domain spectrum-shaped vector based on the above-mentioned cyclically expanded vector and the above-mentioned channel-dependent-transmission spectrum-shaped vector; A step of assigning the above frequency-domain spectrum-shaped vector to a subcarrier of an assigned frequency range; and A DFT-spread OFDM transmitter comprising the step of generating the DFT-spread OFDM signal based on a vector assigned to the above subcarrier.

15. A method performed by a Discrete Fourier Transform (DFT)-spread Orthogonal Frequency Division Multiplexing (OFDM) receiver in a wireless communication system, A step of determining information regarding the channel and information regarding interference-noise between the DFT-spread OFDM transmitter and the DFT-spread OFDM receiver; When an LMMSE (linear minimum mean square error) optimality criterion is set, a step of determining a channel-dependent receiving spectrum shaping vector such that the LMMSE is minimized based on information regarding the channel and information regarding the interference-noise; and The method includes the step of transmitting information regarding the generation of a channel-dependent transmit spectrum forming vector corresponding to the channel-dependent receive spectrum forming vector to the DFT-spread OFDM transmitter. A method for determining the channel-dependent-transmit spectrum shaping vector in the DFT-spread OFDM transmitter based on information regarding the generation of the channel-dependent-transmit spectrum shaping vector.

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