Apparatus and method for performing radar operation in wireless communication system

Abstract

The purpose of the present disclosure is to perform a radar operation in a wireless communication system, and an operation method of a communication device may comprise the steps of: generating at least one codeword by encoding information bits; generating modulation symbols on the basis of the at least one codeword; transmitting signals including the modulation symbols; and when reflected signals corresponding to the signals are received, performing a radar operation by using the reflected signals. Interference signals for the reflected signals can be estimated and removed on the basis of information regarding subcarriers corresponding to the transmitted signals.

Description

Device and method for performing radar operation in a wireless communication system

[0001] The following description relates to a wireless communication system, and to a device and method for performing radar operations in a wireless communication system.

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

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

[0004] The present disclosure can provide a device and method for effectively performing data communication and radar operation in a wireless communication system.

[0005] The present disclosure can provide a device and method for removing an interference signal included in a received signal when a radar operates in a wireless communication system.

[0006] The present disclosure can provide a device and method for transmitting a signal using a subcarrier pre-allocated for radar operation in a wireless communication system.

[0007] The present disclosure can provide a device and method for removing interference signals for reflected signals based on information about subcarriers of a transmitted signal during radar operation in a wireless communication system.

[0008] The present disclosure can provide a device and method for detecting a strong target signal based on the magnitude of received signals during radar operation in a wireless communication system.

[0009] The present disclosure can provide a device and method for estimating time and frequency offsets of interference signals for reflected signals during radar operation in a wireless communication system.

[0010] The present disclosure can provide a device and method for acquiring a weak target signal based on the time and frequency offset of an interference signal during radar operation in a wireless communication system.

[0011] The present disclosure can provide a device and method for detecting a target based on a signal from which interference has been removed during radar operation in a wireless communication system.

[0012] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other technical tasks not mentioned can be considered by a person having ordinary skill in the technical field to which the technical configuration of the present disclosure is applied from the embodiments of the present disclosure described below.

[0013] According to one example of the present disclosure, a method of operating a communication device in a wireless communication system may include the steps of generating at least one codeword by encoding information bits, generating modulation symbols based on the at least one codeword, transmitting signals including the modulation symbols, and, when reflected signals corresponding to the signals are received, performing a radar operation using the reflected signals. An interference signal for the reflected signals may be estimated and removed based on information about a subcarrier corresponding to the transmitted signals.

[0014] According to one example of the present disclosure, a communication device in a wireless communication system includes a transceiver including a plurality of transmitters and a plurality of receivers, and a processor connected to the transceiver, wherein the processor generates at least one codeword by encoding information bits, generates modulation symbols based on the at least one codeword, transmits signals including the modulation symbols, and, when reflected signals corresponding to the signals are received, performs a radar operation using the reflected signals, and an interference signal for the reflected signals can be estimated and removed based on information about a subcarrier corresponding to the transmitted signals.

[0015] According to one example of the present disclosure, a communication device includes at least one processor, and at least one computer memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, direct operations, the operations including: generating at least one codeword by encoding information bits; generating modulation symbols based on the at least one codeword; transmitting signals including the modulation symbols; and performing a radar operation using the reflected signals when reflected signals corresponding to the signals are received, wherein an interference signal for the reflected signals can be estimated and removed based on information about a subcarrier corresponding to the transmitted signals.

[0016] According to one example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction includes at least one instruction executable by a processor, the at least one instruction controlling a device to generate at least one codeword by encoding information bits, generate modulation symbols based on the at least one codeword, transmit signals including the modulation symbols, and, when reflected signals corresponding to the signals are received, perform a radar operation using the reflected signals, wherein an interference signal for the reflected signals can be estimated and canceled based on information about a subcarrier corresponding to the transmitted signals.

[0017] The above-described aspects of the present disclosure are only some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the present disclosure can be derived and understood by a person having ordinary skill in the art based on the detailed description of the present disclosure to be described below.

[0018] The following effects may be achieved by embodiments based on the present disclosure.

[0019] According to the present disclosure, interference signals can be effectively removed during radar operation.

[0020] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure is applied, from the description of the embodiments of the present disclosure below. In other words, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived from the embodiments of the present disclosure by those skilled in the art.

[0021] The accompanying drawings are intended to aid understanding of the present disclosure and may provide embodiments of the present disclosure along with detailed descriptions. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0022] Figure 1 illustrates an example of a communication system applicable to the present disclosure.

[0023] Figure 2 illustrates an example of a wireless device applicable to the present disclosure.

[0024] FIG. 3 illustrates another example of a wireless device applicable to the present disclosure.

[0025] Figure 4 illustrates an example of a portable device applicable to the present disclosure.

[0026] FIG. 5 illustrates an example of a vehicle or autonomous vehicle applicable to the present disclosure.

[0027] Figure 6 illustrates an example of AI (Artificial Intelligence) applicable to the present disclosure.

[0028] FIG. 7 illustrates a method for processing a transmission signal applicable to the present disclosure.

[0029] FIG. 8 illustrates an example of a communication structure that can be provided in a 6G (6th generation) system applicable to the present disclosure.

[0030] Figure 9 illustrates an electromagnetic spectrum applicable to the present disclosure.

[0031] Figure 10 illustrates a THz communication method applicable to the present disclosure.

[0032] Figure 11 illustrates a zeroing technique for removing interference signals.

[0033] Figure 12 illustrates a linear prediction technique for removing interference signals.

[0034] Figure 13 illustrates an example of an interference signal and a target signal.

[0035] FIG. 14 illustrates an example of occurrence of mutual interference between orthogonal frequency division multiplexing (OFDM) radars in a system supporting wireless communication and radar sensing according to one embodiment of the present disclosure.

[0036] Figure 15 shows an example of a received signal containing interference.

[0037] FIG. 16 illustrates an example of an OFDM waveform structure for radar operation according to one embodiment of the present disclosure.

[0038] FIG. 17 illustrates an example of a communication device according to one embodiment of the present disclosure.

[0039] FIG. 18 illustrates an example of a procedure for performing a radar operation according to one embodiment of the present disclosure.

[0040] FIG. 19 illustrates an example of a procedure for removing an interference signal according to one embodiment of the present disclosure.

[0041] FIG. 20 illustrates an example of a detailed procedure for removing an interference signal according to one embodiment of the present disclosure.

[0042] Figures 21a to 21d illustrate simulation results for an interference removal method according to a prior art and an embodiment of the present disclosure.

[0043] FIG. 22a illustrates a simulation environment for an interference removal method according to one embodiment of the present disclosure.

[0044] FIGS. 22b and 22c illustrate examples of performance graphs for an interference removal method according to one embodiment of the present disclosure.

[0045] FIG. 23a and FIG. 23b illustrate examples of performance graphs for interference signal cancellation by modulation scheme according to one embodiment of the present disclosure.

[0046] The following embodiments combine the components and features of the present disclosure in a predetermined form. Each component or feature may be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, some components and / or features may be combined to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

[0047] In the description of the drawings, procedures or steps that may obscure the gist of the present disclosure are not described, and procedures or steps that can be understood by a person skilled in the art are also not described.

[0048] Throughout the specification, when a part is said to "comprising" or "including" a component, this does not mean that other components may be included, but rather that other components may be excluded, unless otherwise specifically stated. In addition, terms such as "...part," "...unit," and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. In addition, the words "a" or "an," "one," "the," and similar related words may be used in the context of describing the present disclosure (especially in the context of the claims below) to include both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0049] Embodiments of the present disclosure described herein focus on the data transmission and reception relationship between a base station and a mobile station. Here, the base station is understood as a terminal node of a network that directly communicates with the mobile station. Certain operations described herein as being performed by the base station may, in some cases, be performed by an upper node of the base station.

[0050] That is, in a network consisting of multiple network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this case, the term 'base station' may be replaced by terms such as fixed station, Node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.

[0051] Additionally, in the embodiments of the present disclosure, the term terminal may be replaced with terms such as user equipment (UE), mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, or advanced mobile station (AMS).

[0052] Additionally, a transmitter refers to a fixed and / or mobile node that provides data or voice services, and a receiver refers to a fixed and / or mobile node that receives data or voice services. Therefore, for uplink, a mobile station can be the transmitter, and a base station can be the receiver. Similarly, for downlink, a mobile station can be the receiver, and a base station can be the transmitter.

[0053] Embodiments of the present disclosure may be supported by standard documents disclosed in at least one of wireless access systems, such as IEEE 802.xx system, 3rd Generation Partnership Project (3GPP) system, 3GPP Long Term Evolution (LTE) system, 3GPP 5G (5th generation) NR (New Radio) system and 3GPP2 system, and in particular, embodiments of the present disclosure may be supported by 3GPP TS (technical specification) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPP TS 38.331 documents.

[0054] Furthermore, the embodiments of the present disclosure can be applied to other wireless access systems and are not limited to the systems described above. For example, they can be applied to systems implemented after the 3GPP 5G NR system and are not limited to a specific system.

[0055] That is, obvious steps or parts not described in the embodiments of the present disclosure can be explained by referring to the above documents. In addition, all terms disclosed in this document can be explained by the above standard documents.

[0056] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the technical configurations of the present disclosure may be implemented.

[0057] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding of the present disclosure, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present disclosure.

[0058] The following technology can be applied to various wireless access systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access).

[0059] In order to clarify the following description, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical idea of ​​the present disclosure is not limited thereto. LTE may refer to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 may be referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 may be referred to as LTE-A pro. 3GPP NR may refer to technology after TS 38.xxx Release 15. 3GPP 6G may refer to technology after TS Release 17 and / or Release 18. “xxx” refers to a standard document detail number. LTE / NR / 6G may be collectively referred to as a 3GPP system.

[0060] For background information, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to this disclosure. For example, reference may be made to standard documents 36.xxx and 38.xxx.

[0061] Communication system applicable to the present disclosure

[0062] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the present disclosure disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0063] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0064] FIG. 1 is a diagram illustrating an example of a communication system applied to the present disclosure.

[0065] Referring to FIG. 1, a communication system (100) applied to the present disclosure includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (extended reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI (artificial intelligence) device / server (100g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicles (100b-1, 100b-2) may include unmanned aerial vehicles (UAVs) (e.g., drones). The XR devices (100c) include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. The portable devices (100d) may include smartphones, smart pads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.), etc. The home appliances (100e) may include TVs, refrigerators, washing machines, etc. The IoT devices (100f) may include sensors, smart meters, etc. For example, the base station (120) and the network (130) may also be implemented as wireless devices, and a specific wireless device (120a) may act as a base station / network node to other wireless devices.

[0066] Wireless devices (100a to 100f) can be connected to a network (130) via a base station (120). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (100g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (120) / network (130), but can also communicate directly (e.g., sidelink communication) without going through the base station (120) / network (130). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). In addition, IoT devices (100f) (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0067] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base stations (120), and base stations (120) / base stations (120). Here, the wireless communication / connection can be established through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and communication between base stations (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and base station / wireless device, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of the present disclosure, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc. may be performed.

[0068] Communication system applicable to the present disclosure

[0069] FIG. 2 is a diagram illustrating an example of a wireless device applicable to the present disclosure.

[0070] Referring to FIG. 2, the first wireless device (200a) and the second wireless device (200b) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (200a), the second wireless device (200b)} can correspond to {the wireless device (100x), the base station (120)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 1.

[0071] A first wireless device (200a) includes one or more processors (202a) and one or more memories (204a), and may further include one or more transceivers (206a) and / or one or more antennas (208a). The processor (202a) controls the memories (204a) and / or the transceivers (206a), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202a) may process information in the memory (204a) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (206a). In addition, the processor (202a) may receive a wireless signal including second information / signals via the transceivers (206a), and then store information obtained from signal processing of the second information / signals in the memory (204a). The memory (204a) may be connected to the processor (202a) and may store various information related to the operation of the processor (202a). For example, the memory (204a) may perform some or all of the processes controlled by the processor (202a), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. Here, the processor (202a) and the memory (204a) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206a) may be connected to the processor (202a) and may transmit and / or receive wireless signals via one or more antennas (208a). The transceiver (206a) may include a transmitter and / or a receiver. The transceiver (206a) may be used interchangeably with an RF (radio frequency) unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0072] The second wireless device (200b) includes one or more processors (202b), one or more memories (204b), and may further include one or more transceivers (206b) and / or one or more antennas (208b). The processor (202b) controls the memories (204b) and / or the transceivers (206b), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202b) may process information in the memory (204b) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206b). In addition, the processor (202b) may receive a wireless signal including fourth information / signals via the transceivers (206b), and then store information obtained from the signal processing of the fourth information / signals in the memory (204b). The memory (204b) may be connected to the processor (202b) and may store various information related to the operation of the processor (202b). For example, the memory (204b) may perform some or all of the processes controlled by the processor (202b), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. Here, the processor (202b) and the memory (204b) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206b) may be connected to the processor (202b) and may transmit and / or receive wireless signals via one or more antennas (208b). The transceiver (206b) may include a transmitter and / or a receiver. The transceiver (206b) may be used interchangeably with an RF unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0073] Hereinafter, the hardware elements of the wireless device (200a, 200b) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (202a, 202b). For example, one or more processors (202a, 202b) may implement one or more layers (e.g., functional layers such as physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and service data adaptation protocol (SDAP)). One or more processors (202a, 202b) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. One or more processors (202a, 202b) may generate messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. One or more processors (202a, 202b) may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed herein, and provide the signals to one or more transceivers (206a, 206b). One or more processors (202a, 202b) may receive signals (e.g., baseband signals) from one or more transceivers (206a, 206b) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0074] One or more processors (202a, 202b) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (202a, 202b) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors (202a, 202b). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software configured to perform one or more processors (202a, 202b) or stored in one or more memories (204a, 204b) and executed by one or more processors (202a, 202b). The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0075] One or more memories (204a, 204b) may be coupled to one or more processors (202a, 202b) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (204a, 204b) may be configured as read only memory (ROM), random access memory (RAM), erasable programmable read only memory (EPROM), flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories (204a, 204b) may be located internally and / or externally to the one or more processors (202a, 202b). Additionally, the one or more memories (204a, 204b) may be coupled to the one or more processors (202a, 202b) via various technologies, such as wired or wireless connections.

[0076] One or more transceivers (206a, 206b) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this document, to one or more other devices. One or more transceivers (206a, 206b) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this document, from one or more other devices. For example, one or more transceivers (206a, 206b) can be coupled to one or more processors (202a, 202b) and can transmit and receive wireless signals. For example, one or more processors (202a, 202b) can control one or more transceivers (206a, 206b) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (202a, 202b) may control one or more transceivers (206a, 206b) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (206a, 206b) may be coupled to one or more antennas (208a, 208b), and one or more transceivers (206a, 206b) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document, via one or more antennas (208a, 208b). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (206a, 206b) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (202a, 202b).One or more transceivers (206a, 206b) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (202a, 202b) from baseband signals to RF band signals. For this purpose, one or more transceivers (206a, 206b) may include an (analog) oscillator and / or filter.

[0077] Wireless device structure applicable to the present disclosure

[0078] FIG. 3 is a diagram illustrating another example of a wireless device applied to the present disclosure.

[0079] Referring to FIG. 3, the wireless device (300) corresponds to the wireless devices (200a, 200b) of FIG. 2 and may be composed of various elements, components, units, and / or modules. For example, the wireless device (300) may include a communication unit (310), a control unit (320), a memory unit (330), and additional elements (340). The communication unit may include a communication circuit (312) and a transceiver(s) (314). For example, the communication circuit (312) may include one or more processors (202a, 202b) and / or one or more memories (204a, 204b) of FIG. 2. For example, the transceiver(s) (314) may include one or more transceivers (206a, 206b) and / or one or more antennas (208a, 208b) of FIG. 2. The control unit (320) is electrically connected to the communication unit (310), the memory unit (330), and the additional elements (340) and controls the overall operation of the wireless device. For example, the control unit (320) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (330). In addition, the control unit (320) may transmit information stored in the memory unit (330) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (310), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (330).

[0080] The additional element (340) may be configured in various ways depending on the type of the wireless device. For example, the additional element (340) may include at least one of a power unit / battery, an input / output unit, a driving unit, and a computing unit. Although not limited thereto, the wireless device (300) may be implemented in the form of a robot (Fig. 1, 100a), a vehicle (Fig. 1, 100b-1, 100b-2), an XR device (Fig. 1, 100c), a portable device (Fig. 1, 100d), a home appliance (Fig. 1, 100e), an IoT device (Fig. 1, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 1, 140), a base station (Fig. 1, 120), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0081] In FIG. 3, various elements, components, units / parts, and / or modules within the wireless device (300) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (310). For example, within the wireless device (300), the control unit (320) and the communication unit (310) may be wired, and the control unit (320) and the first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (310). In addition, each element, component, unit / part, and / or module within the wireless device (300) may further include one or more elements. For example, the control unit (320) may be composed of a set of one or more processors. For example, the control unit (320) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (330) may be composed of RAM, DRAM (dynamic RAM), ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0082] Mobile devices to which the present disclosure applies

[0083] FIG. 4 is a drawing illustrating an example of a mobile device applied to the present disclosure.

[0084] Figure 4 illustrates an example of a mobile device applicable to the present disclosure. The mobile device may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), or a portable computer (e.g., a laptop, etc.). The mobile device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

[0085] Referring to FIG. 4, the portable device (400) may include an antenna unit (408), a communication unit (410), a control unit (420), a memory unit (430), a power supply unit (440a), an interface unit (440b), and an input / output unit (440c). The antenna unit (408) may be configured as a part of the communication unit (410). Blocks 410 to 430 / 440a to 440c correspond to blocks 310 to 330 / 340 of FIG. 3, respectively.

[0086] The communication unit (410) can transmit and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The control unit (420) can control components of the portable device (400) to perform various operations. The control unit (420) can include an AP (application processor). The memory unit (430) can store data / parameters / programs / codes / commands required for operating the portable device (400). In addition, the memory unit (430) can store input / output data / information, etc. The power supply unit (440a) supplies power to the portable device (400) and can include a wired / wireless charging circuit, a battery, etc. The interface unit (440b) can support connection between the portable device (400) and other external devices. The interface unit (440b) can include various ports (e.g., audio input / output ports, video input / output ports) for connection with external devices. The input / output unit (440c) can input or output video information / signals, audio information / signals, data, and / or information input from a user. The input / output unit (440c) may include a camera, a microphone, a user input unit, a display unit (440d), a speaker, and / or a haptic module.

[0087] For example, in the case of data communication, the input / output unit (440c) obtains information / signals (e.g., touch, text, voice, image, video) input by the user, and the obtained information / signals can be stored in the memory unit (430). The communication unit (410) can convert the information / signals stored in the memory into wireless signals, and transmit the converted wireless signals directly to other wireless devices or to a base station. In addition, the communication unit (410) can receive wireless signals from other wireless devices or base stations, and then restore the received wireless signals to the original information / signals. The restored information / signals can be stored in the memory unit (430) and then output in various forms (e.g., text, voice, image, video, haptic) through the input / output unit (440c).

[0088] Types of wireless devices to which the present disclosure applies

[0089] FIG. 5 is a drawing illustrating an example of a vehicle or autonomous vehicle to which the present disclosure applies.

[0090] Figure 5 illustrates a vehicle or autonomous vehicle applicable to the present disclosure. The vehicle or autonomous vehicle may be implemented as a mobile robot, car, train, manned / unmanned aerial vehicle (AV), ship, etc., and is not limited to the form of a vehicle.

[0091] Referring to FIG. 5, a vehicle or autonomous vehicle (500) may include an antenna unit (508), a communication unit (510), a control unit (520), a driving unit (540a), a power supply unit (540b), a sensor unit (540c), and an autonomous driving unit (540d). The antenna unit (550) may be configured as a part of the communication unit (510). Blocks 510 / 530 / 540a to 540d correspond to blocks 410 / 430 / 440 of FIG. 4, respectively.

[0092] The communication unit (510) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations, etc.), servers, etc. The control unit (520) can control elements of a vehicle or autonomous vehicle (500) to perform various operations. The control unit (520) can include an electronic control unit (ECU).

[0093] Figure 6 is a diagram illustrating an example of an AI device applicable to the present disclosure. For example, the AI ​​device may be implemented as a fixed or mobile device, such as a TV, projector, smartphone, PC, laptop, digital broadcasting terminal, tablet PC, wearable device, set-top box (STB), radio, washing machine, refrigerator, digital signage, robot, or vehicle.

[0094] Referring to FIG. 6, the AI ​​device (600) may include a communication unit (610), a control unit (620), a memory unit (630), an input / output unit (640a / 640b), a learning processor unit (640c), and a sensor unit (640d). Blocks 610 to 630 / 640a to 640d may correspond to blocks 310 to 330 / 340 of FIG. 3, respectively.

[0095] The communication unit (610) can transmit and receive wired and wireless signals (e.g., sensor information, user input, learning models, control signals, etc.) with external devices such as other AI devices (e.g., FIG. 1, 100x, 120, 140) or AI servers (FIG. 1, 140) using wired and wireless communication technology. To this end, the communication unit (610) can transmit information within the memory unit (630) to the external device or transfer a signal received from the external device to the memory unit (630).

[0096] The control unit (620) may determine at least one executable operation of the AI ​​device (600) based on information determined or generated using a data analysis algorithm or a machine learning algorithm. In addition, the control unit (620) may control components of the AI ​​device (600) to perform the determined operation. For example, the control unit (620) may request, search, receive, or utilize data from the learning processor unit (640c) or the memory unit (630), and may control components of the AI ​​device (600) to perform a predicted operation or an operation determined to be desirable among at least one executable operation. In addition, the control unit (620) may collect history information including the operation contents of the AI ​​device (600) or user feedback on the operation, and store the collected history information in the memory unit (630) or the learning processor unit (640c), or transmit the collected history information to an external device such as an AI server (FIG. 1, 140). The collected history information may be used to update a learning model.

[0097] The memory unit (630) can store data that supports various functions of the AI ​​device (600). For example, the memory unit (630) can store data obtained from the input unit (640a), data obtained from the communication unit (610), output data of the learning processor unit (640c), and data obtained from the sensing unit (640). In addition, the memory unit (630) can store control information and / or software codes necessary for the operation / execution of the control unit (620).

[0098] The input unit (640a) can obtain various types of data from the outside of the AI ​​device (600). For example, the input unit (620) can obtain learning data for model learning, input data to which the learning model will be applied, etc. The input unit (640a) may include a camera, a microphone, and / or a user input unit. The output unit (640b) may generate output related to vision, hearing, or touch. The output unit (640b) may include a display unit, a speaker, and / or a haptic module, etc. The sensing unit (640) can obtain at least one of internal information of the AI ​​device (600), information about the surrounding environment of the AI ​​device (600), and user information using various sensors. The sensing unit (640) may include a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and / or a radar, etc.

[0099] The learning processor unit (640c) can train a model composed of an artificial neural network using learning data. The learning processor unit (640c) can perform AI processing together with the learning processor unit of the AI ​​server (Fig. 1, 140). The learning processor unit (640c) can process information received from an external device via the communication unit (610) and / or information stored in the memory unit (630). In addition, the output value of the learning processor unit (640c) can be transmitted to an external device via the communication unit (610) and / or stored in the memory unit (630).

[0100] FIG. 7 is a diagram illustrating a method for processing a transmission signal applied to the present disclosure. For example, the transmission signal may be processed by a signal processing circuit. At this time, the signal processing circuit (700) may include a scrambler (710), a modulator (720), a layer mapper (730), a precoder (740), a resource mapper (750), and a signal generator (760). At this time, as an example, the operations / functions of FIG. 7 may be performed in the processors (202a, 202b) and / or the transceivers (206a, 206b) of FIG. 2. Furthermore, as an example, the hardware elements of FIG. 7 may be implemented in the processors (202a, 202b) and / or the transceivers (206a, 206b) of FIG. 2. As an example, blocks 710 to 760 may be implemented in the processors (202a, 202b) of FIG. 2. Additionally, blocks 710 to 750 may be implemented in the processor (202a, 202b) of FIG. 2, and block 760 may be implemented in the transceiver (206a, 206b) of FIG. 2, and are not limited to the above-described embodiment.

[0101] The codeword can be converted into a wireless signal through the signal processing circuit (700) of FIG. 7. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transport block (e.g., a UL-SCH transport block, a DL-SCH transport block). The wireless signal may be transmitted through various physical channels (e.g., a PUSCH, a PDSCH). Specifically, the codeword can be converted into a bit sequence scrambled by a scrambler (710). The scramble sequence used for scrambling is generated based on an initialization value, and the initialization value may include ID information of the wireless device, etc. The scrambled bit sequence can be modulated into a modulation symbol sequence by a modulator (720). The modulation scheme may include pi / 2-binary phase shift keying (pi / 2-BPSK), m-phase shift keying (m-PSK), m-quadrature amplitude modulation (m-QAM), etc.

[0102] A complex modulation symbol sequence can be mapped to one or more transmission layers by a layer mapper (730). The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (740) (precoding). The output z of the precoder (740) can be obtained by multiplying the output y of the layer mapper (730) by an N*M precoding matrix W. Here, N is the number of antenna ports, and M is the number of transmission layers. Here, the precoder (740) can perform precoding after performing transform precoding (e.g., discrete Fourier transform (DFT) transform) on the complex modulation symbols. In addition, the precoder (740) can perform precoding without performing transform precoding.

[0103] The resource mapper (750) can map modulation symbols of each antenna port to time-frequency resources. The time-frequency resources can include multiple symbols (e.g., CP-OFDMA symbols, DFT-s-OFDMA symbols) in the time domain and multiple subcarriers in the frequency domain. The signal generator (760) generates a wireless signal from the mapped modulation symbols, and the generated wireless signal can be transmitted to another device through each antenna. To this end, the signal generator (760) can include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), a frequency uplink converter, and the like.

[0104] The signal processing process for receiving signals in a wireless device can be configured in reverse order of the signal processing process (710 to 760) of FIG. 7. For example, a wireless device (e.g., 200a and 200b of FIG. 2) can receive wireless signals from the outside through an antenna port / transceiver. The received wireless signals can be converted into baseband signals through a signal restorer. For this purpose, the signal restorer can include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Thereafter, the baseband signal can be restored to a codeword through a resource demapper process, a postcoding process, a demodulation process, and a descrambling process. The codewords can be restored to the original information blocks through decoding. Accordingly, a signal processing circuit (not shown) for a received signal may include a signal restorer, a resource de-mapper, a postcoder, a demodulator, a de-scrambler, and a decoder.

[0105] 6G communication system

[0106] The 6G (wireless communication) system aims to achieve (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) low energy consumption for battery-free IoT devices, (vi) ultra-reliable connectivity, and (vii) connected intelligence with machine learning capabilities. The vision of the 6G system can be divided into four aspects: "intelligent connectivity," "deep connectivity," "holographic connectivity," and "ubiquitous connectivity," and the 6G system can satisfy the requirements as shown in Table 1 below. In other words, Table 1 is a table showing the requirements of the 6G system.

[0107] Per device peak data rate1 TbpsE2E latency1 msMaximum spectral efficiency100 bps / HzMobility supportup to 1000 km / hrSatellite integrationFullyAIFullyAutonomous vehicleFullyXRFullyHaptic CommunicationFully

[0108] At this time, the 6G system may have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine type communications (mMTC), AI integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0109] FIG. 8 is a diagram illustrating an example of a communication structure that can be provided in a 6G system applicable to the present disclosure.

[0110] Referring to Figure 8, 6G systems are expected to have 50 times higher simultaneous wireless connectivity than 5G wireless systems. URLLC, a key feature of 5G, is expected to become a more prominent technology in 6G communications, providing end-to-end latency of less than 1 ms. Furthermore, 6G systems will have significantly better volumetric spectral efficiency, unlike the commonly used area spectral efficiency. 6G systems can offer extremely long battery life and advanced battery technologies for energy harvesting, eliminating the need for separate charging for mobile devices in 6G systems.

[0111] Core implementation technology of 6G systems

[0112] - Artificial Intelligence (AI)

[0113] The most crucial and newly introduced technology for 6G systems is AI. 4G systems did not involve AI. 5G systems will support partial or very limited AI. However, 6G systems will fully support AI for automation. Advances in machine learning will create more intelligent networks for real-time communications in 6G. Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analyses to determine how complex target tasks should be performed. In other words, AI can increase efficiency and reduce processing delays.

[0114] Time-consuming tasks such as handover, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0115] Recent attempts to integrate AI into wireless communication systems have focused on the application layer and network layer, particularly deep learning in wireless resource management and allocation. However, this research is increasingly evolving to the MAC layer and physical layer, with attempts to combine deep learning with wireless transmission, particularly in the physical layer. AI-based physical layer transmission refers to the application of signal processing and communication mechanisms based on AI drivers, rather than traditional communication frameworks, in terms of fundamental signal processing and communication mechanisms. For example, this may include deep learning-based channel coding and decoding, deep learning-based signal estimation and detection, deep learning-based multiple input multiple output (MIMO) mechanisms, and AI-based resource scheduling and allocation.

[0116] Machine learning can be used for channel estimation and channel tracking, as well as for power allocation and interference cancellation at the physical layer of the downlink (DL). Machine learning can also be used for antenna selection, power control, and symbol detection in MIMO systems.

[0117] However, the application of DNN for transmission at the physical layer may have the following problems.

[0118] Deep learning-based AI algorithms require a large amount of training data to optimize training parameters. However, due to limitations in obtaining training data from specific channel environments, a large amount of training data is used offline. This means that static training on training data in specific channel environments can lead to conflicts with the dynamic characteristics and diversity of the wireless channel.

[0119] Furthermore, current deep learning primarily targets real-world signals. However, signals at the physical layer of wireless communications are complex signals. Further research is needed on neural networks capable of detecting complex domain signals to match the characteristics of wireless communication signals.

[0120] Below, we will look at machine learning in more detail.

[0121] Machine learning refers to a series of operations that train machines to perform tasks that humans can or cannot perform. Machine learning requires data and a learning model. In machine learning, data learning methods can be broadly categorized into three types: supervised learning, unsupervised learning, and reinforcement learning.

[0122] Neural network training aims to minimize output errors. It involves repeatedly inputting training data into a neural network, calculating the neural network output and target error for the training data, and backpropagating the neural network error from the output layer to the input layer to update the weights of each node in the neural network to reduce the error.

[0123] Supervised learning uses labeled training data, while unsupervised learning may not have labeled training data. For example, in the case of supervised learning for data classification, the training data may be data in which each training data category is labeled. The labeled training data is input to a neural network, and the error can be calculated by comparing the output (categories) of the neural network with the training data labels. The calculated error is backpropagated through the neural network in the backward direction (i.e., from the output layer to the input layer), and the connection weights of each node in each layer of the neural network can be updated through backpropagation. The amount of change in the connection weights of each updated node can be determined by the learning rate. The neural network's calculation of the input data and the backpropagation of the error can constitute a learning cycle (epoch). The learning rate can be applied differently depending on the number of iterations of the neural network's learning cycle. For example, in the early stages of training a neural network, a high learning rate can be used to quickly allow the network to achieve a certain level of performance, thereby increasing efficiency. In the later stages of training, a low learning rate can be used to increase accuracy.

[0124] Learning methods may vary depending on the characteristics of the data. For example, if the goal is to accurately predict data transmitted by a transmitter in a communication system, supervised learning is preferable to unsupervised learning or reinforcement learning.

[0125] The learning model corresponds to the human brain, and the most basic linear model can be thought of, but the machine learning paradigm that uses highly complex neural network structures, such as artificial neural networks, as learning models is called deep learning.

[0126] The neural network cores used in learning methods are mainly deep neural networks (DNN), convolutional deep neural networks (CNN), and recurrent Boltzmann machines (RNN), and these learning models can be applied.

[0127] THz (Terahertz) communication

[0128] THz communications can be applied in 6G systems. For example, data transmission rates can be increased by increasing bandwidth. This can be achieved by using sub-THz communications with wide bandwidths and applying advanced massive MIMO technology.

[0129] FIG. 9 is a diagram illustrating an electromagnetic spectrum applicable to the present disclosure. For example, referring to FIG. 9, THz waves, also known as sub-millimeter radiation, typically represent a frequency band between 0.1 THz and 10 THz with a corresponding wavelength ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (Sub-THz band) is considered a major portion of the THz band for cellular communications. Adding the Sub-THz band to the mmWave band will increase the capacity of 6G cellular communications. Among the defined THz bands, 300 GHz to 3 THz is in the far infrared (IR) frequency band. Although the 300 GHz to 3 THz band is part of the optical band, it is at the boundary of the optical band and lies just behind the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0130] Key characteristics of THz communications include (i) the widely available bandwidth to support very high data rates and (ii) the high path loss that occurs at high frequencies (requiring highly directional antennas). The narrow beamwidths generated by highly directional antennas reduce interference. The small wavelength of THz signals allows for a significantly larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array technologies to overcome range limitations.

[0131] Terahertz (THz) wireless communications

[0132] FIG. 10 is a diagram illustrating a THz communication method applicable to the present disclosure.

[0133] Referring to Fig. 10, THz wireless communication is a wireless communication using THz waves with a frequency of approximately 0.1 to 10 THz (1 THz = 1012 Hz), and may refer to terahertz (THz) band wireless communication using a very high carrier frequency of 100 GHz or higher. THz waves are located between the RF (Radio Frequency) / millimeter (mm) and infrared bands, and (i) compared to visible light / infrared rays, they penetrate non-metallic / non-polarizable materials well, and compared to RF / millimeter waves, they have a shorter wavelength, so they have high straightness and can enable beam focusing.

[0134] Specific embodiments of the present invention

[0135] The present disclosure relates to a technique for performing a radar operation in a system supporting wireless communication and radar sensing. Specifically, the present disclosure describes a technique for removing an interference signal generated by frequency sharing in a system supporting wireless communication and radar sensing. The present disclosure proposes a method for estimating and removing an interference signal using an OFDM waveform as various embodiments for removing mutual interference between OFDM radars implemented by inserting a pre-allocated subcarrier into an OFDM radar waveform in a system supporting wireless communication and radar sensing. The present disclosure is applicable to various existing communication systems as well as 6G (6 th It can be used to simultaneously operate high-performance sensing and communication in systems of 6G and beyond (beyond 6G). The present disclosure can be used in various application fields such as communication using sensing and sensing using communication.

[0136] Recently, digital radars capable of embedding data into radar waveforms have been gaining attention, replacing the traditional analog FMCW (Frequency Modulated Continuous Wave) radar. These radars include PMCW (Phase Modulated Continuous Wave), which modulates phase, and OFDM radar, which uses the OFDM waveform widely used in existing communications. Digital radars offer several advantages, including their simultaneous use for radar sensing and communications, and the ability to freely manipulate waveforms because signals can be generated digitally.

[0137] However, in systems combining OFDM radar (digital radar) and communications, frequency interference issues between communication devices due to frequency sharing are expected to worsen. In particular, among joint communications and sensing (JCAS) use cases, such as outdoor vehicular communication and sensing systems or indoor communication and sensing systems that may be in dense environments, interference between communication devices may increase further. Accordingly, several techniques, such as zeroing and linear prediction, have been proposed to address interference between radar signals between communication devices.

[0138] Figure 11 illustrates a zeroing technique for removing interference signals. Referring to Figure 11, the zeroing technique is a technique for reconstructing an interference region (1105) by replacing data in an interference region (1105) that overlaps an interference signal (1103) in a reflected signal (1101) received after being reflected by a target with a zero value.

[0139] Figure 12 illustrates a linear prediction technique for removing interference signals. Referring to Figure 12, the linear prediction technique is a technique for reconstructing data in an interference region (1205) that overlaps with an interference signal (1203) in a reflected signal (1201) received after being reflected by a target, based on data in a non-interfered section.

[0140] However, the method of replacing data in the interference area (1105) of the reflection signal (1101) with a zero value, as shown in FIG. 11, has a problem in that the data loss rate increases as the interference area (1105) becomes larger. In addition, when reconstructing data in the interference area (1205) of the reflection signal (1201) based on data in an area where interference does not occur, as shown in FIG. 12, there is a problem in that the accuracy of the reconstructed data may decrease depending on the data ratio of the area where interference does not occur and the interference area.

[0141] Moreover, the zeroing technique and the linear prediction technique have a problem in that they cannot be applied in certain situations, as illustrated in Fig. 13. Fig. 13 illustrates an example of an interference signal and a target signal. As illustrated in Fig. 13, when the area of ​​the interference signal (1303) is larger than the area of ​​the reflected signal (1301), the entire area of ​​the reflected signal (1301) overlaps with the interference signal (1303), and therefore, the zeroing technique or the linear prediction technique cannot be applied.

[0142] Considering the aforementioned problems, the present disclosure relates to a technique for eliminating interference signals generated by frequency sharing in systems supporting wireless communications and radar sensing. The present disclosure proposes a technique for eliminating mutual interference between OFDM radars, implemented by inserting pre-allocated subcarriers into OFDM radar waveforms. Furthermore, the present disclosure proposes a technique for estimating and eliminating interference signals using OFDM waveforms.

[0143] First, a situation in which mutual interference occurs between OFDM radars in a system supporting wireless communication and radar sensing according to an embodiment of the present disclosure will be examined as follows. FIG. 14 illustrates an example of mutual interference occurring between OFDM radars in a system supporting wireless communication and radar sensing according to an embodiment of the present disclosure. Specifically, FIG. 14 illustrates a situation in which interference occurs by a fourth device (1440) when a first device (1410) supporting wireless communication and radar sensing attempts to sense at least one target (1420, 1430, 1440) using radar operation.

[0144] Referring to FIG. 14, a first device (1410) transmits a first signal (1412) for radar operation. In one embodiment, the first signal (1412) may be a signal designated or designed for radar operation. However, the embodiments of the present disclosure are not limited thereto. For example, the first signal (1412) may be a signal containing data and / or information to be transmitted to another device.

[0145] A first signal (1412) transmitted from a first device (1410) is reflected by at least one target (1420, 1430, 1440). The signal (1422) reflected by at least one target (1420, 1430, 1440) is received by the first device (1410). In other words, the first device (1410) can receive the reflected signal (1422) corresponding to the transmitted first signal (1412). In this case, when the fourth device (1440) transmits the second signal (1442), the second signal (1442) can be received by the first device (1410). The second signal (1442) may be a signal designated or designed for a radar function, or a signal including data and / or information to be transmitted to a specific device.

[0146] The second signal (1442) received by the first device (1410) may act as an interference signal for the reflected signal (1422). That is, the first device (1410) may receive a signal including the reflected signal (1422) and the second signal (1442), which is an interference signal thereto, as illustrated in FIG. 15. FIG. 15 illustrates an example of a received signal including interference. Referring to FIG. 15, it can be confirmed that the noise level of the received signal including interference is higher than that of the received signal not including interference. This means that the noise level of the received signal of the first device (1410) increases due to the interference of the second signal (1442) transmitted from the fourth device (1440). When the noise level of the received signal is high, it is difficult for the first device (1410) to accurately sense at least one target (1420, 1430, 1440). Accordingly, the first device (1410) according to one embodiment of the present disclosure can sense at least one target (1420, 1430, 1440) by using the interference-removed signal after removing an interference signal (e.g., a second signal (1442)) included in a received signal.

[0147] As previously mentioned, interference can degrade sensing performance. Therefore, improving sensing performance by eliminating interference is desired. To eliminate interference signals, systems according to various embodiments of the present disclosure can utilize an OFDM waveform structure designed with interference cancellation in mind. According to one embodiment, an OFDM waveform designed with interference cancellation in mind is illustrated in FIG. 16.

[0148] FIG. 16 illustrates an example of an OFDM waveform structure for radar operation according to an embodiment of the present disclosure. As illustrated in FIG. 16, a device according to an embodiment of the present disclosure utilizes pre-allocated subcarriers (1610) for radar operation. The device may utilize symbols designated in the pre-allocated subcarriers (1610) for radar operation. That is, all devices may be configured to perform transmission and reception operations using symbols designated in the pre-allocated subcarriers (1610) during radar operation.

[0149] Pre-allocated subcarriers (1610) for radar operation are of equal frequency spacing N f can be set to have. For example, the pre-allocated subcarriers (1610) can be set to a frequency comb type that includes subcarriers with the same spacing in all OFDM symbols. When the pre-allocated subcarriers (1610) have a frequency comb type, interference can be estimated regardless of the reception time of the interference signal. However, the embodiments of the present disclosure are not limited thereto. For example, the frequency spacings of the pre-allocated subcarriers (1410) may be different from each other.

[0150] FIG. 17 illustrates an example of a device according to one embodiment of the present disclosure. The components illustrated in FIG. 17 are merely exemplary, and embodiments of the present disclosure are not limited thereto. For example, the device may further include at least one component not illustrated.

[0151] Referring to FIG. 17, the device (1700) may include a transmitter (1710), a receiver (1720), and a radar processor (1730).

[0152] A transmitter (1710) transmits a signal for radar operation using a designated symbol on pre-allocated subcarriers, as illustrated in FIG. 16, for radar operation. The transmitter includes a modulator (1711), a subcarrier allocator (1712), an inverse fast Fourier transform (IFFT) module (1713), a parallel-to-serial converter (1714), a digital-to-analog converter (DAC) (1715), a frequency uplink converter (1716), and a transmission antenna (1717), and can transmit a signal for radar operation using the listed components. For example, the transmitter generates modulation symbols by modulating input bits corresponding to a signal to be transmitted for radar operation according to a designated modulation method using the modulator (1711). Thereafter, the transmitter can perform an IFFT operation on the modulation symbols through the IFFT module (1713) and output IFFT symbols. At this time, the IFFT module (1713) can allocate modulation symbols to subcarriers pre-allocated for radar operation under the control of the subcarrier allocator (1712). Thereafter, the transmitter converts the IFFT symbols provided in parallel into serial through a parallel-to-serial converter (1714) and converts them into analog signals through a DAC (1715) to generate OFDM symbols. The transmitter can up-convert the OFDM symbols to a designated frequency band through a frequency up-converter (1716) and then transmit them through a transmission antenna (1717).

[0153] The receiver (1720) receives a signal including a reflected signal through subcarriers pre-allocated for radar operation. The reflected signal refers to a signal that is reflected by at least one target after being transmitted from a transmitter and reaches the receiver. The receiver includes a receiving antenna (1727), a frequency downlink converter (1726), an analog-to-digital converter (ADC) (1725), a serial to parallel converter (1724), a fast Fourier transform (FFT) module (1723), and a parallel-to-serial converter (1721), and receives a signal including a reflected signal through the listed components. For example, the receiver can down-convert OFDM symbols received through the receiving antenna (1727) into signals of a designated frequency band and then convert them into digital symbols through the ADC (1725). The receiver can convert serial digital symbols into parallel ones through a serial-to-parallel converter (1724) and perform an FFT operation through an FFT (1723) to generate parallel modulation symbols. Thereafter, the receiver can output the parallel modulation symbols through the parallel-to-serial converter (1724).

[0154] A radar processor (1730) obtains information about at least one target by removing interference signals included in received signals based on information about subcarriers of a transmitted signal and performing radar operations based on the interference-removed signal. The radar processor (1730) may include an interference cancellation processing module (1731), an element-wise division module (1733), a range processing module (1735), and a Doppler processing module (1737).

[0155] The interference cancellation processing module (1731) removes first target signals that satisfy a specified condition from modulation symbols corresponding to the received signal, and then estimates and removes the interference signal based on information about the subcarrier of the transmitted signal. The specified condition may be a condition regarding the magnitude of the received signal. For example, the interference cancellation processing module (1731) may determine that the magnitude of the modulation symbols is greater than the specified magnitude, and may remove the first target signal. The first target signal may be a strong signal reflected and received by at least one target adjacent to the device (1700). According to one embodiment, the specified magnitude may be determined based on the waveform of the transmitted signal. In addition, the information about the subcarrier of the transmitted signal may include at least one of a frequency interval of subcarriers of a signal transmitted for radar operation, or a time interval of OFDM symbols. That is, the interference cancellation processing module (173) estimates the frequency offset and time offset of the interference signal based on information about the subcarrier of the transmission signal, removes the frequency offset and time offset of the estimated interference signal, and then estimates unknown symbol values ​​of the interference signal. The interference cancellation processing module (1731) reconstructs the interference signal using the estimated symbol values, and then removes the reconstructed interference signal from the signal from which the strong signal has been removed, thereby obtaining a second target signal. The second target signal may be a weak signal reflected and received by at least one target that is not adjacent to the device (1700). The interference cancellation processing module (1731) combines the first target signal and the second target signal to obtain a signal from which interference has been mitigated.

[0156] The interference removal processing module (1731) performs a radar operation to sense a target based on a signal from which interference has been mitigated using an element-wise division module (1733), a range processing module (1735), and a Doppler processing module (1737).

[0157] FIG. 18 illustrates an example of a procedure for performing a radar operation according to one embodiment of the present disclosure. FIG. 18 illustrates an operation method of a device (e.g., a base station or UE) that transmits a signal for sensing.

[0158] Referring to FIG. 18, in step S1801, the device generates signals. Here, the signals may include data signals and signal sequences for radar operation. For example, the device may generate information bits, generate at least one codeword by encoding the information bits, perform scrambling on bits within the at least one codeword, and generate modulation symbols by modulating the scrambled bits. That is, the device may generate data signals by performing at least one operation of encoding, scrambling, and modulation. At this time, the device may generate a signal according to a coding rate and modulation method assigned by a base station. In addition, the device may generate a signal sequence for radar operation. At this time, the signal sequence may be generated according to a predefined rule for radar operation or may be generated based on information bits that convey data. If the signal sequence for radar operation is generated based on information bits, the signal sequence may include modulation symbols through encoding, scrambling, modulation, etc.

[0159] In step S1803, the device transmits a signal including a signal for radar operation. The device may map data signals and a signal sequence for radar operation to subcarriers pre-allocated for radar operation, and then generate OFDM symbols and transmit the OFDM symbols. At this time, the signal for radar operation may be mapped to the pre-allocated subcarriers. The pre-allocated subcarriers may include subcarriers having the same frequency spacing. For example, the pre-allocated subcarriers may be configured as a frequency comb type including subcarriers having the same spacing in all OFDM symbols. However, embodiments of the present disclosure are not limited thereto. For example, the frequency spacings of the pre-allocated subcarriers may be different from each other.

[0160] In step S1805, the device performs a radar operation using reflected signals. That is, the device receives reflected signals generated when the signal transmitted in step S1803 is reflected by at least one target. Here, an interference signal may be received together with the reflected signals. The device may estimate an interference signal included in the received signals based on information about a subcarrier of the transmitted signal, and may remove the estimated interference signal from the received signals. The device may perform a radar operation for sensing a target based on the interference-removed reflected signal, thereby detecting at least one of a distance to a target object, a relative angle with respect to the target object, and a moving speed of the target object.

[0161] FIG. 19 illustrates an example of a procedure for removing interference signals according to one embodiment of the present disclosure. FIG. 19 illustrates an operation method of a device (e.g., a base station or UE) that transmits a signal for sensing. The interference signal removal procedure of FIG. 19 can be understood as a specific procedure for step S1805 of FIG. 18.

[0162] Referring to FIG. 19, at step S1901, the device receives signals including reflection signals of a transmission signal. The received signals may include not only reflection signals but also interference signals that are not reflection signals. The interference signals may be transmission signals for radar operation of another device.

[0163] In step S1903, the device removes the first target signal from the received signals. For example, the device may detect the first target signal based on the magnitude of the received signals and remove the detected first target signal from the received signals. For example, the device may determine a signal satisfying a predefined condition from the received signals as a first target signal that is reflected by at least one adjacent target and is a strong target signal received, and remove the first target signal from the received signals. According to one embodiment, the predefined condition is defined based on the waveform of the transmitted signal and may be related to the magnitude of the signal.

[0164] In step S1905, the device obtains a second target signal by estimating and removing interference. For example, the device may estimate an interference signal based on information about subcarriers of a transmission signal in a first signal from which the first target signal has been removed, and obtain a second target signal by removing the estimated interference signal. The information about subcarriers of the transmission signal may include at least one of a frequency interval of subcarriers of the transmission signal or a time interval of OFDM symbols. The device may obtain a second target signal, which is a weak target signal, by removing an interference signal from a signal from which the first target signal, which is a strong target signal, has been removed.

[0165] In step S1907, the device senses a target based on a first target signal and a second target signal. For example, the device may obtain information about at least one target by combining the first target signal, which is a strong target signal, and the second target signal, which is a weak target signal, to obtain a reflected signal with reduced interference, and perform a radar operation based on the reflected signal with reduced interference. The information about at least one target may include information about at least one adjacent target corresponding to the strong target signal, and information about at least one non-adjacent target corresponding to the weak target signal.

[0166] In the embodiment described with reference to FIG. 19, the device removes the first target signal from the received signals. Here, the first target signal is a signal that satisfies a predefined condition. However, a signal that satisfies the predefined condition may not exist. In this case, step S1903 is omitted, and the device can perform step S1905 on the received signals.

[0167] FIG. 20 illustrates a detailed procedure for removing interference signals according to one embodiment of the present disclosure. FIG. 20 illustrates an operating method of a device (e.g., a base station or UE) that transmits signals for sensing. The detailed procedure for removing interference signals in FIG. 20 can be understood as a specific procedure for FIG. 19.

[0168] Referring to FIG. 20, in step S2001, the device receives signals including reflection signals for a transmitted signal. Here, the transmitted signal includes a signal for radar operation. For example, after transmitting a signal for radar operation, the device receives signals including reflection signals for the transmitted signal. At this time, the device may receive a radar signal transmitted from at least one other target, and the received radar signal may act as interference to the reflection signals.

[0169] In step S2003, the device determines whether a first target signal exists among the received signals. The device can determine whether a first target signal satisfying a predefined condition exists based on a waveform of a transmitted signal. The first target signal is a signal reflected and received by at least one target located near the device, and can be detected based on the magnitude of the received signals without removing interference signals. For example, the device can determine whether a signal having a signal-to-noise ratio (SNR) of about 10 dB or greater exists among the received signals. The device can determine a signal having an SNR of about 10 dB or greater as the first target signal.

[0170] If the first target signal does not exist among the received signals, the device proceeds to step S2009. For example, if there is no signal with an SNR of 10 dB or higher among the received signals, the device may determine that the first target signal does not exist and proceed to step S2009.

[0171] If the first target signal is present in the received signal, the device reconstructs the first target signal in step S2005. For example, if a signal having an SNR of 10 dB or higher is present among the received signals, the device determines that the first target signal is present and can reconstruct the first target signal. At this time, the device can reconstruct the first target signal based on the modulation symbol of the transmitted signal. This is because the first target signal is a signal returned by being reflected by at least one target adjacent to the device.

[0172] In step S2007, the device removes the first target signal from the received signals. The device may remove the reconstructed first target signal from the received signals to estimate the interference signal included in the received signals. By removing the first target signal, the interference signal becomes the main component in the remaining signal, and thus, the remaining signal may be referred to as an interference-dominant signal.

[0173] In step S2009, the device estimates the delay and Doppler effect of the interference signal using information about the subcarriers of the transmission signal. That is, the device can estimate the time and frequency offset of the interference signal in the interference dominant signal from which the first target signal has been removed based on the information about the subcarriers of the transmission signal. For example, the information about the subcarriers of the transmission signal may include, as illustrated in FIG. 16, the frequency interval between the subcarriers of the transmission signal. , or the time interval of OFDM symbols At least one of the following may be included. At this time, the frequency offset of the interference signal may be expressed as a phase difference between OFDM symbols, and the time offset of the interference signal may be expressed as a phase difference between subcarriers. That is, the device may, based on information about the subcarriers of the transmission signal, calculate the phase difference on the time axis between the subcarriers corresponding to the transmission signal and the subcarriers of the interference dominant signal. , and phase difference along the frequency axis can be measured and / or calculated. refers to the phase difference due to the frequency offset of the interference signal, refers to the phase difference due to the time offset of the interference signal.

[0174] In step S2011, the device compensates for the delay and Doppler effect of the interference signal and estimates the modulation symbol values ​​of the interference signal. The device can remove the time and frequency offset of the estimated interference signal from the subcarriers, respectively, and estimate the unknown symbol values ​​of the interference signal. For example, the device may receive a signal from the mth OFDM symbol and the nth subcarrier. By performing a division operation, time and frequency offsets can be removed and the modulation symbols of the interference signal can be demodulated.

[0175] In step S2013, the device obtains a second target signal by removing an interference signal from the interference dominant signal. For example, the device may reconstruct the interference signal again based on the demodulation result for the interference signal and remove the reconstructed interference signal from the interference dominant signal. Accordingly, the device can obtain a second target signal. The second target signal may be a weak signal reflected and received by at least one target that is not adjacent to the device. That is, the device can obtain a second target signal having an SNR of less than 10 dB.

[0176] In step S2015, the device obtains an interference-mitigated signal based on the second target signal. If the first target signal exists, the interference-mitigated signal may include the first target signal and the second target signal. For example, if the determination result of step S2003 determines that the first target signal exists, the device may obtain an interference-mitigated signal by combining the first target signal and the second target signal. If the first target signal does not exist, the interference-mitigated signal may include only the second target signal. For example, if the determination result of step S2003 determines that the first target signal does not exist, the device may determine the second target signal as the interference-mitigated signal.

[0177] In step S2017, the device senses at least one target using the interference-mitigated signal. For example, the device may acquire information about at least one target by performing a radar operation based on the interference-mitigated signal. The information about at least one target may include at least one of information about at least one adjacent target corresponding to a first target signal, or information about at least one non-adjacent target corresponding to a second target signal.

[0178] FIGS. 21A to 21D illustrate simulation results for interference removal methods according to the prior art and an embodiment of the present disclosure. Specifically, FIG. 21A shows the result of detecting a target without removing the interference signal in a situation where the received signal includes an interference signal, and FIG. 21B shows the result of detecting a target after removing the interference signal as proposed in the present disclosure. In addition, FIG. 21C shows the result of detecting a target after removing the interference signal according to the zeroing technique, and FIG. 21D shows the result of detecting a target after removing the interference signal according to the linear prediction technique. Referring to FIGS. 21A to 21D , it can be seen that when detecting targets after removing the interference signal as proposed in the present disclosure, the largest number of targets are accurately detected. This is because the method proposed in the present disclosure accurately estimates the interference signal and removes the estimated interference signal, so the impact on the target signal is very small, whereas the zeroing technique and the linear prediction technique remove the portion of the received signal where interference occurs or reduce the amplitude, resulting in loss of data of the target signal.

[0179] FIG. 22a illustrates a simulation environment for an interference removal method according to one embodiment of the present disclosure, and FIGS. 22b and 22c illustrate examples of performance graphs for an interference removal method according to one embodiment of the present disclosure.

[0180] Referring to Figure 22a, for the simulation, it is assumed that Target 1 and Target 2 are located approximately 3.9 m and 5.9 m away from the victim radar, respectively, and the interference radar is located approximately 1.7 m away.

[0181] Referring to Fig. 22b, when simulating in an environment as shown in Fig. 22a, when an interference signal is present, targets are not identified due to the noise level caused by the interference signal, but when the interference signal is removed as proposed in the present disclosure, the noise level is lowered and both Target 1 and Target 2 are identified.

[0182] Referring to FIG. 22b, it can be seen that the zeroing technique and the linear prediction technique reduce the peak values ​​corresponding to Target 1 and Target 2 after removing the interference signal from the received signal. On the other hand, it can be seen that the peak values ​​of Target 1 and Target 2 do not reduce when the interference signal is removed as proposed in the present disclosure. In other words, when using the method for removing the interference signal as proposed in the present disclosure, a higher signal-to-nose-and-interference ratio (SNIR) can be obtained compared to existing methods.

[0183] Figures 23a and 23b illustrate examples of performance graphs for interference signal removal by modulation scheme according to one embodiment of the present disclosure. Figure 23a shows the interference signal removal results when the modulation scheme is QPSK, and Figure 23b shows the interference signal removal results when the modulation scheme is 16-QAM.

[0184] Referring to FIGS. 23a and 23b, when the 16-QAM modulation method is applied, when the magnitude of the interference signal is about 10 dB or more compared to when QPSK is applied, the interference signal can be removed using the algorithm proposed in the present disclosure.

[0185] As described above, the present disclosure proposes a method and device for eliminating mutual interference between OFDM radars caused by frequency sharing in a system supporting wireless communication and radar sensing. Through this, the proposed technology enables simultaneous operation of high-performance sensing and communication in future 6G and wireless network environments. Furthermore, the proposed technology can be expanded to various applications, such as sensing-based communication and communication-based sensing.

[0186] The proposed methods described above can be implemented independently, but they can also be implemented as a combination (or merge) of some of the proposed methods. Rules can be defined so that the base station notifies the terminal of the applicability of the proposed methods (or information about the rules of the proposed methods) through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0187] The present disclosure may be embodied in other specific forms without departing from the technical ideas and essential features described herein. Therefore, the above detailed description should not be construed as limiting in all respects but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are intended to be included within the scope of the present disclosure. Furthermore, claims that are not explicitly cited in the claims may be combined to form an embodiment or incorporated into a new claim through a post-filing amendment.

[0188] Embodiments of the present disclosure can be applied to various wireless access systems. Examples of various wireless access systems include the 3rd Generation Partnership Project (3GPP) or 3GPP2 systems.

[0189] The embodiments of the present disclosure can be applied not only to the various wireless access systems described above, but also to all technical fields that utilize these various wireless access systems. Furthermore, the proposed method can also be applied to mmWave and THz communication systems utilizing ultra-high frequency bands.

[0190] Additionally, embodiments of the present disclosure can be applied to various applications such as autonomous vehicles and drones.

Claims

1. In a method of operating a communication device in a wireless communication system, A step of generating at least one codeword by encoding information bits; A step of generating modulation symbols based on at least one codeword; A step of generating at least one orthogonal frequency division multiplexing (OFDM) symbol including the above modulation symbols; a step of transmitting at least one OFDM symbol; and When reflected signals corresponding to signals for radar operation included in the above OFDM symbols are received, a step of performing a radar operation using the reflected signals is included. A method for estimating and removing interference signals for the above reflected signals based on information about subcarriers allocated for signals for the above radar operation.

2. In claim 1, A method in which the information about the subcarriers includes at least one of the frequency intervals of the subcarriers allocated for the radar operation or the time intervals of OFDM symbols.

3. In claim 2, A method in which the subcarriers allocated for the above radar operation are set to a frequency comb type including subcarriers spaced at designated OFDM symbols.

4. In claim 1, A method in which the signals for the above radar operation include a signal sequence generated by a predefined rule for the above radar operation.

5. In claim 1, A method in which signals for the above radar operation are generated based on information bits that convey data.

6. In claim 1, The step of performing radar operation using the above reflected signals is: A step of receiving signals including the reflected signals and the interference signal; A step of determining whether there is a first target signal reflected by at least one target adjacent to the communication device based on the magnitude of the received signals; A method comprising the step of estimating and removing the interference signal included in the interference dominant signal determined based on the presence or absence of the first target signal.

7. In claim 6, A method in which the interference dominant signal is determined by removing the first target signal from the received signals, if the first target signal exists.

8. In claim 6, A method in which the interference dominant signal comprises the received signals when the first target signal does not exist.

9. In claim 6, A method wherein the first target signal includes a signal that satisfies a predefined condition among the received signals.

10. In claim 6, The step of estimating and removing the interference signal included in the above interference dominant signal is: A step of estimating at least one of a time offset and a frequency offset of the interference signal based on information about a subcarrier corresponding to the transmitted signals; A method comprising the step of removing the interference signal from the interference dominant signal using at least one of the estimated time offset and the frequency offset.

11. In claim 10, The time offset of the above interference signal is determined based on the phase difference in the frequency axis of the received signals, A method in which the frequency offset of the above interference signal is determined based on the phase difference on the time axis of the received signals.

12. In claim 6, The step of performing radar operation using the above reflected signals is: A step of performing the radar operation based on the signal from which the interference signal has been removed and the first target signal when the first target signal exists; and A method comprising the step of performing the radar operation based on a signal from which the interference signal has been removed when the first target signal does not exist.

13. In a communication device in a wireless communication system, A transceiver comprising a plurality of transmitters and a plurality of receivers; and A processor connected to the above transmitter and receiver is included, The above processor, Generate at least one codeword by encoding information bits, Generating modulation symbols based on at least one codeword, Transmitting signals including the above modulation symbols, When reflected signals corresponding to the above signals are received, the radar operation is controlled to be performed using the reflected signals, A communication device in which interference signals for the reflected signals are estimated and removed based on information about subcarriers corresponding to the transmitted signals.

14. In communication devices, At least one processor; At least one computer memory connected to said at least one processor and storing instructions that direct operations when executed by said at least one processor, The above actions are, A step of generating at least one codeword by encoding information bits; A step of generating modulation symbols based on at least one codeword; A step of transmitting signals including the above modulation symbols; When reflected signals corresponding to the above signals are received, a step of performing radar operation using the reflected signals is included. A communication device in which interference signals for the reflected signals are estimated and removed based on information about subcarriers corresponding to the transmitted signals.

15. In a non-transitory computer-readable medium storing at least one instruction, comprising at least one instruction executable by the processor, At least one of the above commands causes the device to: Generate at least one codeword by encoding information bits, Generating modulation symbols based on at least one codeword, Transmitting signals including the above modulation symbols, When reflected signals corresponding to the above signals are received, the radar operation is controlled to be performed using the reflected signals, A communication device in which interference signals for the reflected signals are estimated and removed based on information about subcarriers corresponding to the transmitted signals.

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