Method and apparatus for transmitting and receiving signal in wireless communication system

Abstract

According to various embodiments of the present disclosure, a method performed by a first node in a communication system may comprise the steps of: generating a transmission signal including transmission data and at least one reference signal; dividing the transmission signal into a plurality of subbands; deriving a precoder for the transmission signal on the basis of the plurality of subbands; applying the precoder to the transmission signal; and transmitting the transmission signal to a second node, wherein the at least one reference signal can include a first reference signal used to estimate the precoder at the second node.

Description

Method and device for transmitting and receiving signals in a wireless communication system

[0001] The present disclosure relates to a method and device for transmitting and receiving signals in a wireless communication system. Specifically, the present disclosure relates to a method and device for transmitting a reference signal so that a precoder can be estimated at a receiving end of 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 a 6G channel environment using the terahertz (Thz) band, there may be a situation where the transmission power must be increased compared to the conventional one to overcome path attenuation. In a communication system based on orthogonal frequency division multiplexing (OFDM), the power structure design can be designed based on the peak-to-average-ratio (PAPR). At this time, since multiple subcarrier signals are merged and transmitted in the time domain, there may be a time-domain signal with a higher transmission power than the average transmission power, and a problem may arise in that the transmission power cannot be implemented to the desired level due to the peak value of the signal. To solve this problem, precoder-based PAPR reduction algorithms have been discussed in the past. However, the conventional technologies had the problem of increasing the overall system complexity because the precoder value had to be transmitted to the receiver on a symbol-by-symbol basis.

[0004] To solve the above-described problems, the present disclosure provides a device and method for performing signal transmission and reception in a wireless communication system.

[0005] Additionally, the present disclosure provides a device and method for transmitting and receiving a reference signal in a wireless communication system.

[0006] Additionally, the present disclosure provides a device and method for estimating a precoder in a wireless communication system.

[0007] According to various embodiments of the present disclosure, a method performed by a first node in a communication system includes the steps of generating a transmission signal including transmission data and at least one reference signal, dividing the transmission signal into a plurality of subbands, deriving a precoder for the transmission signal based on the plurality of subbands, applying the precoder to the transmission signal, and transmitting the transmission signal to a second node, wherein the at least one reference signal may include a first reference signal used to estimate the precoder in the second node.

[0008] According to various embodiments of the present disclosure, the first reference signal may be included in at least one symbol constituting the sub-band.

[0009] According to various embodiments of the present disclosure, the precoder can be derived for each of the plurality of sub-bands.

[0010] According to various embodiments of the present disclosure, the step of applying the precoder to the transmission signal may include the step of generating a mitigation matrix using the precoder and the step of applying the mitigation matrix to the transmission signal.

[0011] According to various embodiments of the present disclosure, the step of deriving the precoder may include the step of estimating the precoder based on the number of the plurality of sub-bands, the step of estimating a peak-to-average power ratio (PAPR) of the transmission signal based on the precoder, and the step of deriving the precoder based on whether the estimated PAPR exceeds a preset PAPR.

[0012] According to various embodiments of the present disclosure, based on the estimated PAPR not exceeding the preset PAPR, the precoder can be derived as an estimated precoder based on the number of the plurality of sub-bands.

[0013] According to various embodiments of the present disclosure, based on the estimated PAPR exceeding the preset PAPR, the precoder can be derived based on a precoder that is recursively estimated based on the number of sub-bands into which the plurality of sub-bands are recursively divided.

[0014] According to various embodiments of the present disclosure, the plurality of sub-bands can be recursively divided based on multiples of a preset number.

[0015] According to various embodiments of the present disclosure, the at least one reference signal includes at least one of a Demodulation Reference Signal (DMRS) and a Phase Tracking Reference Signal (PTRS), wherein the precoder may not be applied to the DMRS and PTRS.

[0016] According to various embodiments of the present disclosure, the transmission signal may not include the derived precoder.

[0017] According to various embodiments of the present disclosure, a method performed by a second node in a communication system may include the steps of receiving a transmission signal including data and at least one reference signal from a first node, performing channel estimation based on the transmission signal, estimating a precoder for the transmission signal based on the transmission signal and the channel, and obtaining data included in the transmission signal based on the channel and the precoder.

[0018] According to various embodiments of the present disclosure, the at least one reference signal includes a Demodulation Reference Signal (DMRS), and the channel can be estimated based on the DMRS.

[0019] According to various embodiments of the present disclosure, the at least one reference signal may include a first reference signal used to estimate the precoder.

[0020] According to various embodiments of the present disclosure, the precoder can be estimated based on at least one of the channel, the DMRS, and the first reference signal.

[0021] According to various embodiments of the present disclosure, a first node operating in a communication system includes a transceiver, at least one processor, and at least one memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations, wherein the operations may include all steps of a method of operating the first node according to various embodiments of the present disclosure.

[0022] According to various embodiments of the present disclosure, a second node operating in a communication system includes a transceiver, at least one processor, and at least one memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations, wherein the operations may include all steps of a method of operating the second node according to various embodiments of the present disclosure.

[0023] According to various embodiments of the present disclosure, a control device for controlling a first node in a communication system includes at least one processor and at least one memory operably connected to the at least one processor, wherein the at least one memory stores instructions for performing operations based on being executed by the at least one processor, and the operations may include all steps of an operating method of the first node according to various embodiments of the present disclosure.

[0024] According to various embodiments of the present disclosure, a control device for controlling a second node in a communication system includes at least one processor and at least one memory operably connected to the at least one processor, wherein the at least one memory stores instructions for performing operations based on being executed by the at least one processor, and the operations may include all steps of an operating method of the second node according to various embodiments of the present disclosure.

[0025] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media storing one or more instructions, wherein the one or more instructions, when executed by one or more processors, perform operations, the operations including all steps of a method of operating a first node according to various embodiments of the present disclosure.

[0026] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media storing one or more instructions, wherein the one or more instructions, when executed by one or more processors, perform operations, the operations including all steps of a method of operating a second node according to various embodiments of the present disclosure.

[0027] According to the present disclosure, a device and method for performing signal transmission and reception in a wireless communication system can be provided.

[0028] Additionally, according to the present disclosure, a device and method for transmitting and receiving a reference signal in a wireless communication system can be provided.

[0029] Additionally, according to the present disclosure, a device and method for estimating a precoder in a wireless communication system can be provided.

[0030] In addition, according to the present disclosure, since the receiver can directly estimate the precoder, there is an effect of reducing the system complexity for precoder transmission.

[0031] The accompanying drawings are intended to aid understanding of the present disclosure and, together with detailed descriptions, may provide embodiments of the present disclosure. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0032] Figure 1 is a diagram illustrating an example of physical channels and general signal transmission used in a 3GPP system.

[0033] Figure 2 is a diagram illustrating the system structure of a New Generation Radio Access Network (NG-RAN).

[0034] Figure 3 is a diagram illustrating the functional division between NG-RAN and 5GC.

[0035] Figure 4 is a diagram illustrating an example of a 5G usage scenario.

[0036] Figure 5 is a diagram illustrating an example of a communication structure that can be provided in a 6G system.

[0037] Figure 6 is a diagram illustrating an example of an electromagnetic spectrum.

[0038] Figure 7 is a diagram illustrating an example of a THz communication application.

[0039] Fig. 8 is a diagram illustrating an example of an electronic component-based THz wireless communication transmitter and receiver.

[0040] FIG. 9 is a diagram illustrating an example of a method for generating a THz signal based on an optical element.

[0041] Fig. 10 is a diagram illustrating an example of an optical element-based THz wireless communication transceiver.

[0042] Fig. 11 is a diagram illustrating the structure of a photon source-based transmitter.

[0043] Figure 12 is a drawing showing the structure of an optical modulator.

[0044] FIG. 13 is a drawing for explaining a reference signal structure to which the present disclosure can be applied.

[0045] FIG. 14 is a diagram illustrating an example of a reference signal transmission structure according to the present disclosure.

[0046] FIG. 15 is a diagram for explaining the performance of a reference signal according to the present disclosure.

[0047] FIG. 16 is another drawing illustrating an example of a reference signal transmission structure according to the present disclosure.

[0048] FIG. 17 is a drawing for explaining a signal transmission method according to the present disclosure.

[0049] FIG. 18 is another drawing for explaining a signal transmission method according to the present disclosure.

[0050] FIG. 19 is a diagram for explaining an OFDM symbol according to the present disclosure.

[0051] FIG. 20 is a diagram for explaining a sub-band signal configuration according to the present disclosure.

[0052] FIG. 21 is another diagram for explaining a sub-band signal configuration according to the present disclosure.

[0053] Figure 22 is a drawing for explaining a mitigation matrix according to the present disclosure.

[0054] FIG. 23 is another diagram for explaining the performance of a reference signal according to the present disclosure.

[0055] FIG. 24 is a diagram illustrating an example of a reference signal generation method according to the present disclosure.

[0056] FIG. 25 is a drawing for explaining a signal receiving method according to the present disclosure.

[0057] FIG. 26 is another diagram for explaining the performance of a reference signal according to the present disclosure.

[0058] FIG. 27 is another diagram for comparing the performance of reference signals according to the present disclosure.

[0059] Figure 28 is a drawing for explaining a data loading method according to the present disclosure.

[0060] Figure 29 is a drawing for explaining the performance of a data loading method according to the present disclosure.

[0061] FIG. 30 is a diagram illustrating an example of a method for a first node to transmit and receive a signal in a system applicable to the present disclosure.

[0062] FIG. 31 is a diagram illustrating an example of a method for a second node to transmit and receive signals in a system applicable to the present disclosure.

[0063] FIG. 32 illustrates a communication system (1) applicable to various embodiments of the present disclosure.

[0064] FIG. 33 illustrates a wireless device that can be applied to various embodiments of the present disclosure.

[0065] FIG. 34 illustrates another example of a wireless device that can be applied to various embodiments of the present disclosure.

[0066] Figure 35 illustrates a signal processing circuit for a transmission signal.

[0067] FIG. 36 illustrates another example of a wireless device applicable to various embodiments of the present disclosure.

[0068] In various embodiments of the present disclosure, “A or B” may mean “only A,” “only B,” or “both A and B.” In other words, in various embodiments of the present disclosure, “A or B” may be interpreted as “A and / or B.” For example, in various embodiments of the present disclosure, “A, B or C” may mean “only A,” “only B,” “only C,” or “any combination of A, B and C.”

[0069] In various embodiments of the present disclosure, a slash ( / ) or a comma may mean "and / or." For example, "A / B" may mean "A and / or B." Accordingly, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

[0070] In various embodiments of the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Furthermore, in various embodiments of the present disclosure, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted as equivalent to “at least one of A and B.”

[0071] Additionally, in various embodiments of the present disclosure, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C.”

[0072] Additionally, parentheses used in various embodiments of the present disclosure may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in various embodiments of the present disclosure is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0073] Technical features individually described in a single drawing in various embodiments of the present disclosure may be implemented individually or simultaneously.

[0074]

[0075] The following technologies can be used in various wireless access systems, such as CDMA, FDMA, TDMA, OFDMA, and SC-FDMA. CDMA can be implemented using wireless technologies such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented using wireless technologies such as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented using wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is a part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro. 3GPP 6G may be an evolved version of 3GPP NR.

[0076]

[0077] For clarity, the description is based on 3GPP communication systems (e.g., LTE, NR, etc.), but the technical spirit of the present disclosure is not limited thereto. LTE refers to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 is referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 is referred to as LTE-A pro. 3GPP NR refers 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. For background technology, terms, abbreviations, etc. used in the description of the present disclosure, reference may be made to matters described in standard documents published prior to the present disclosure. For example, reference may be made to the following documents.

[0078]

[0079] 3GPP LTE

[0080] - 36.211: Physical channels and modulation

[0081] - 36.212: Multiplexing and channel coding

[0082] - 36.213: Physical layer procedures

[0083] - 36.300: Overall description

[0084] - 36.331: Radio Resource Control (RRC)

[0085] 3GPP NR

[0086] - 38.211: Physical channels and modulation

[0087] - 38.212: Multiplexing and channel coding

[0088] - 38.213: Physical layer procedures for control

[0089] - 38.214: Physical layer procedures for data

[0090] - 38.300: NR and NG-RAN Overall Description

[0091] - 38.331: Radio Resource Control (RRC) protocol specification

[0092]

[0093] Physical Channel and Frame Structure

[0094] Physical channels and general signal transmission

[0095] Figure 1 is a diagram illustrating an example of physical channels and general signal transmission used in a 3GPP system.

[0096] In a wireless communication system, a terminal receives information from a base station via the downlink (DL) and transmits it to the base station via the uplink (UL). The information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type and purpose of the information being transmitted and received.

[0097] When a terminal is powered on or enters a new cell, it performs an initial cell search operation, such as synchronizing with the base station (S11). To this end, the terminal receives a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell ID. Afterwards, the terminal can receive a Physical Broadcast Channel (PBCH) from the base station to obtain broadcast information within the cell. Meanwhile, the terminal can receive a Downlink Reference Signal (DL RS) during the initial cell search phase to check the downlink channel status.

[0098] A terminal that has completed initial cell search can obtain more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on information contained in the PDCCH (S12).

[0099] Meanwhile, when accessing a base station for the first time or when there are no radio resources for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (S13 to S16). To this end, the terminal may transmit a specific sequence as a preamble via a physical random access channel (PRACH) (S13 and S15) and receive a response message (RAR (Random Access Response) message) to the preamble via a PDCCH and a corresponding PDSCH. In the case of a contention-based RACH, a contention resolution procedure may additionally be performed (S16).

[0100] The terminal that has performed the procedure described above can then perform PDCCH / PDSCH reception (S17) and physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) transmission (S18) as general uplink / downlink signal transmission procedures. In particular, the terminal can receive downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and different formats can be applied depending on the purpose of use.

[0101] Meanwhile, the control information that the terminal transmits to the base station via the uplink or that the terminal receives from the base station may include downlink / uplink ACK / NACK signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix Index), RI (Rank Indicator), etc. The terminal may transmit the above-described control information such as CQI / PMI / RI via PUSCH and / or PUCCH.

[0102]

[0103] Structure of uplink and downlink channels

[0104] Downlink channel structure

[0105] The base station transmits a related signal to the terminal through a downlink channel described below, and the terminal receives the related signal from the base station through a downlink channel described below.

[0106]

[0107] (1) Physical Downlink Shared Channel (PDSCH)

[0108] PDSCH carries downlink data (e.g., DL-shared channel transport block, DL-SCH TB) and applies modulation methods such as Quadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (QAM), 64 QAM, and 256 QAM. Codewords are generated by encoding the TBs. PDSCH can carry multiple codewords. Scrambling and modulation mapping are performed for each codeword, and modulation symbols generated from each codeword are mapped to one or more layers (Layer mapping). Each layer is mapped to resources along with a Demodulation Reference Signal (DMRS), generated as an OFDM symbol signal, and transmitted through the corresponding antenna port.

[0109]

[0110] (2) Physical downlink control channel (PDCCH)

[0111] The PDCCH carries downlink control information (DCI) and employs modulation methods such as QPSK. A PDCCH consists of 1, 2, 4, 8, or 16 Control Channel Elements (CCEs), depending on the Aggregation Level (AL). Each CCE is comprised of six Resource Element Groups (REGs). Each REG is defined by one OFDM symbol and one (P)RB.

[0112] The UE obtains DCI transmitted via the PDCCH by performing decoding (also known as blind decoding) on ​​a set of PDCCH candidates. The set of PDCCH candidates decoded by the UE is defined as a PDCCH search space set. The search space set may be a common search space or a UE-specific search space. The UE can obtain DCI by monitoring PDCCH candidates within one or more search space sets established by the MIB or higher layer signaling.

[0113]

[0114] Uplink channel structure

[0115] The terminal transmits a related signal to the base station through the uplink channel described below, and the base station receives the related signal from the terminal through the uplink channel described below.

[0116] (1) Physical Uplink Shared Channel (PUSCH)

[0117] PUSCH carries uplink data (e.g., UL-shared channel transport block, UL-SCH TB) and / or uplink control information (UCI), and is transmitted based on a CP-OFDM (Cyclic Prefix - Orthogonal Frequency Division Multiplexing) waveform, a DFT-s-OFDM (Discrete Fourier Transform - spread - Orthogonal Frequency Division Multiplexing) waveform, etc. When the PUSCH is transmitted based on a DFT-s-OFDM waveform, the UE transmits the PUSCH by applying transform precoding. For example, when transform precoding is disabled (e.g., transform precoding is disabled), the UE transmits the PUSCH based on the CP-OFDM waveform, and when transform precoding is enabled (e.g., transform precoding is enabled), the UE can transmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmissions can be dynamically scheduled by UL grants in DCI, or semi-statically scheduled (configured grant) based on higher layer (e.g., RRC) signaling (and / or Layer 1 (L1) signaling (e.g., PDCCH)). PUSCH transmissions can be performed in a codebook-based or non-codebook-based manner.

[0118] (2) Physical Uplink Control Channel (PUCCH)

[0119] PUCCH carries uplink control information, HARQ-ACK and / or scheduling request (SR), and can be divided into multiple PUCCHs depending on the PUCCH transmission length.

[0120]

[0121] Below, we describe new radio access technology (new RAT, NR).

[0122] As more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, massive Machine Type Communications (MTC), which connects numerous devices and objects to provide various services anytime, anywhere, is also a key issue to be considered in next-generation communication. Furthermore, communication system design that considers reliability and latency-sensitive services / terminals is being discussed. The introduction of next-generation radio access technologies that take into account enhanced mobile broadband communication, massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) is being discussed, and in various embodiments of the present disclosure, such technologies are conveniently referred to as new RAT or NR.

[0123]

[0124] Figure 2 is a diagram illustrating the system structure of a New Generation Radio Access Network (NG-RAN).

[0125] Referring to FIG. 2, the NG-RAN may include a gNB and / or an eNB that provides user plane and control plane protocol termination to the UE. FIG. 1 illustrates a case where only a gNB is included. The gNB and eNB are connected to each other via an Xn interface. The gNB and eNB are connected to the 5th generation core network (5G Core Network: 5GC) via the NG interface. More specifically, the gNB is connected to the access and mobility management function (AMF) via the NG-C interface, and the gNB is connected to the user plane function (UPF) via the NG-U interface.

[0126] Figure 3 is a diagram illustrating the functional division between NG-RAN and 5GC.

[0127] Referring to FIG. 3, the gNB can provide functions such as inter-cell radio resource management (Inter Cell RRM), radio bearer management (RB control), connection mobility control (Connection Mobility Control), radio admission control (Radio Admission Control), measurement configuration and provision, and dynamic resource allocation. The AMF can provide functions such as NAS security and idle state mobility processing. The UPF can provide functions such as mobility anchoring and PDU processing. The SMF (Session Management Function) can provide functions such as terminal IP address allocation and PDU session control.

[0128] Figure 4 is a diagram illustrating an example of a 5G usage scenario.

[0129] The 5G usage scenario illustrated in FIG. 4 is merely exemplary, and the technical features of various embodiments of the present disclosure can also be applied to other 5G usage scenarios not illustrated in FIG. 4.

[0130] Referring to Figure 4, the three key requirement areas for 5G include (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC). Some use cases may require optimization across multiple areas, while others may focus on just one key performance indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.

[0131] eMBB focuses on improving data speeds, latency, user density, and overall capacity and coverage of mobile broadband connections. It targets throughputs of around 10 Gbps. eMBB significantly exceeds basic mobile internet access, enabling rich interactive experiences, media and entertainment applications in the cloud, and augmented reality. Data is a key driver of 5G, and for the first time, dedicated voice services may not be available in the 5G era. In 5G, voice is expected to be handled as an application, simply using the data connection provided by the communication system. The increased traffic volume is primarily due to the increasing content size and the growing number of applications that require high data rates. Streaming services (audio and video), interactive video, and mobile internet connectivity will become more prevalent as more devices connect to the internet. Many of these applications require always-on connectivity to push real-time information and notifications to users. Cloud storage and applications are rapidly growing on mobile communication platforms, and this can be applied to both work and entertainment. Cloud storage is a particular use case driving the growth of uplink data rates. 5G is also used for remote work in the cloud, requiring significantly lower end-to-end latency to maintain a superior user experience when tactile interfaces are used. In entertainment, for example, cloud gaming and video streaming are other key factors driving the demand for mobile broadband. Entertainment is essential on smartphones and tablets, regardless of location, including in highly mobile environments like trains, cars, and airplanes. Another use case is augmented reality and information retrieval for entertainment, where augmented reality requires extremely low latency and instantaneous data volumes.

[0132] mMTC is designed to enable communication between a large number of low-cost, battery-powered devices, supporting applications such as smart metering, logistics, field, and body sensors. mMTC targets a battery life of approximately 10 years and / or a population of approximately 1 million devices per square kilometer. mMTC enables seamless connectivity of embedded sensors across all sectors and is one of the most anticipated 5G use cases. The number of IoT devices is projected to reach 20.4 billion by 2020. Industrial IoT is one area where 5G will play a key role, enabling smart cities, asset tracking, smart utilities, agriculture, and security infrastructure.

[0133] URLLC is ideal for vehicle communications, industrial control, factory automation, remote surgery, smart grids, and public safety applications by enabling devices and machines to communicate with high reliability, very low latency, and high availability. URLLC targets latency on the order of 1 ms. URLLC encompasses new services that will transform industries through ultra-reliable, low-latency links, such as remote control of critical infrastructure and autonomous vehicles. This level of reliability and latency is essential for smart grid control, industrial automation, robotics, and drone control and coordination.

[0134] Next, we will look more specifically at a number of usage examples included within the triangle in Fig. 4.

[0135] 5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS) by delivering streams rated at hundreds of megabits per second to gigabits per second. These high speeds may be required to deliver TV at resolutions beyond 4K (6K, 8K, and beyond), as well as virtual reality (VR) and augmented reality (AR). VR and AR applications include near-immersive sports events. Certain applications may require specialized network configurations. For example, for VR gaming, a gaming company may need to integrate its core servers with the network operator's edge network servers to minimize latency.

[0136] Automotive is expected to be a significant new driver for 5G, with numerous use cases for in-vehicle mobile communications. For example, passenger entertainment demands both high capacity and high mobile broadband, as future users will consistently expect high-quality connectivity regardless of their location and speed. Another automotive application is augmented reality dashboards. An AR dashboard allows drivers to identify objects in the dark on top of what they see through the windshield. The AR dashboard overlays information to inform the driver about the distance and movement of objects. In the future, wireless modules will enable vehicle-to-vehicle communication, information exchange between vehicles and supporting infrastructure, and information exchange between vehicles and other connected devices (e.g., devices accompanying pedestrians). Safety systems can guide drivers to safer driving behaviors, reducing the risk of accidents. The next step will be remotely controlled or autonomous vehicles, which require highly reliable and fast communication between different autonomous vehicles and / or between vehicles and infrastructure. In the future, autonomous vehicles will perform all driving tasks, leaving drivers to focus solely on traffic anomalies that the vehicle itself cannot detect. The technological requirements for autonomous vehicles will require ultra-low latency and ultra-high-speed reliability, increasing traffic safety to levels unattainable by humans.

[0137] Smart cities and smart homes, often referred to as smart societies, will be embedded with dense wireless sensor networks. A distributed network of intelligent sensors will identify conditions for cost- and energy-efficient maintenance of cities or homes. Similar setups can be implemented for individual homes. Temperature sensors, window and heating controllers, burglar alarms, and appliances will all be wirelessly connected. Many of these sensors typically require low data rates, low power, and low cost. However, for example, real-time HD video may be required from certain types of devices for surveillance purposes.

[0138] The consumption and distribution of energy, including heat and gas, are becoming increasingly decentralized, requiring automated control of distributed sensor networks. Smart grids interconnect these sensors using digital information and communication technologies to collect and act on information. This information can include the behavior of suppliers and consumers, enabling smart grids to improve efficiency, reliability, economic efficiency, sustainable production, and the automated distribution of fuels like electricity. Smart grids can also be viewed as another low-latency sensor network.

[0139] The health sector has numerous applications that can benefit from mobile communications. Telecommunications systems can support telemedicine, which provides clinical care in remote locations. This can help reduce distance barriers and improve access to health services that are otherwise unavailable in remote rural areas. It can also be used to save lives in critical care and emergency situations. Mobile-based wireless sensor networks can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0140] Wireless and mobile communications are becoming increasingly important in industrial applications. Wiring is expensive to install and maintain. Therefore, the potential to replace cables with reconfigurable wireless links presents an attractive opportunity for many industries. However, achieving this requires wireless connections to operate with similar latency, reliability, and capacity to cables, while simplifying their management. Low latency and extremely low error rates are new requirements for 5G connectivity.

[0141] Logistics and freight tracking are important use cases for mobile communications, enabling the tracking of inventory and packages anywhere using location-based information systems. Logistics and freight tracking typically require low data rates but may require wide-range and reliable location information.

[0142] Below, examples of next-generation communications (e.g., 6G) that can be applied to various embodiments of the present disclosure will be described.

[0143]

[0144] 6G system in general

[0145] 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 an example of the requirements of a 6G system.

[0146] Per device peak data rate1TbpsE2E latency1msMaximum spectral efficiency100bps / HzMobility supportUp to 1000km / hrSatellite integrationFullyAIFullyAutonomous vehicleFullyXRFullyHaptic CommunicationFully

[0147] 6G systems can have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine-type communication (mMTC), AI integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0148] Figure 5 is a diagram illustrating an example of a communication structure that can be provided in a 6G system.

[0149] 6G systems are expected to have 50 times the simultaneous wireless connectivity of 5G systems. URLLC, a key feature of 5G, will become even more crucial in 6G communications by providing end-to-end latency of less than 1 ms. 6G systems will have significantly higher volumetric spectral efficiency, compared to 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. New network characteristics in 6G may include:

[0150] - Satellite integrated network: 6G is expected to integrate with satellites to provide a global mobile network. The integration of terrestrial, satellite, and airborne networks into a single wireless communications system is crucial for 6G.

[0151] Connected Intelligence: Unlike previous generations of wireless communication systems, 6G is revolutionary, upgrading the wireless evolution from "connected objects" to "connected intelligence." AI can be applied at every stage of the communication process (or at every signal processing step, as described below).

[0152] - Seamless integration of wireless information and energy transfer: 6G wireless networks will transfer power to charge the batteries of devices such as smartphones and sensors. Therefore, wireless information and energy transfer (WIET) will be integrated.

[0153] - Ubiquitous super 3D connectivity: Access to networks and core network functions of drones and very low Earth orbit satellites will create super 3D connectivity in 6G ubiquitous.

[0154] Some general requirements for the new network characteristics of 6G, such as the above, may be as follows:

[0155] - Small cell networks: The concept of small cell networks was introduced to improve received signal quality in cellular systems by increasing throughput, energy efficiency, and spectral efficiency. Consequently, small cell networks are essential for 5G and beyond-5G (5GB) communication systems. Accordingly, 6G communication systems also adopt the characteristics of small cell networks.

[0156] Ultra-dense heterogeneous networks: Ultra-dense heterogeneous networks will be another key feature of 6G communication systems. Multi-tier networks comprised of heterogeneous networks improve overall QoS and reduce costs.

[0157] High-capacity backhaul: Backhaul connections are characterized by high-capacity backhaul networks to support high-volume traffic. High-speed fiber optics and free-space optics (FSO) systems may be potential solutions to this problem.

[0158] - Radar technology integrated with mobile technology: High-precision localization (or location-based services) through communications is a key feature of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0159] - Softwarization and virtualization: Softwarization and virtualization are two critical features that form the foundation of the design process for 5GB networks to ensure flexibility, reconfigurability, and programmability. Furthermore, billions of devices can be shared on a shared physical infrastructure.

[0160]

[0161] Core implementation technology of 6G systems

[0162] THz (Terahertz) communication

[0163] Data rates can be increased by increasing bandwidth. This can be achieved by utilizing sub-THz communications with wide bandwidths and applying advanced massive MIMO technology. THz waves, also known as sub-millimeter waves, typically refer to the frequency range between 0.1 THz and 10 THz, with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (sub-THz band) is considered a key part 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 lies in the far infrared (IR) frequency band. While part of the optical band, the 300 GHz to 3 THz band lies at the boundary of the optical band, immediately following the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0164] Figure 6 is a diagram illustrating an example of an electromagnetic spectrum.

[0165] 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.

[0166] Optical wireless technology

[0167] OWC technology is designed for 6G communications, in addition to RF-based communications for all possible device-to-access networks. These networks connect to network-to-backhaul / fronthaul networks. OWC technology has already been used in 4G communication systems, but it will be used more widely to meet the demands of 6G communication systems. OWC technologies such as light fidelity, visible light communication, optical camera communication, and wideband-based FSO communication are already well-known. Communications based on optical wireless technology can provide very high data rates, low latency, and secure communications. LiDAR can also be used for ultra-high-resolution 4D mapping in 6G communications based on wideband.

[0168] FSO backhaul network

[0169] The transmitter and receiver characteristics of an FSO system are similar to those of a fiber-optic network. Therefore, data transmission in an FSO system is similar to that of a fiber-optic system. Therefore, FSO can be a promising technology for providing backhaul connectivity in 6G systems, in conjunction with fiber-optic networks. Using FSO, ultra-long-distance communications are possible, even over distances exceeding 10,000 km. FSO supports high-capacity backhaul connectivity for remote and non-remote areas, such as the ocean, space, underwater, and isolated islands. FSO also supports cellular base station (BS) connections.

[0170] Massive MIMO technology

[0171] One of the key technologies for improving spectral efficiency is the application of MIMO technology. As MIMO technology improves, spectral efficiency also improves. Therefore, massive MIMO technology will be crucial in 6G systems. Because MIMO technology utilizes multiple paths, multiplexing technology must be considered to ensure that data signals can be transmitted along more than one path, as well as beam generation and operation technologies suitable for the THz band.

[0172] Blockchain

[0173] Blockchain will become a crucial technology for managing massive amounts of data in future communication systems. Blockchain is a form of distributed ledger technology. A distributed ledger is a database distributed across numerous nodes or computing devices. Each node replicates and stores an identical copy of the ledger. Blockchains are managed by a peer-to-peer network and can exist without being managed by a central authority or server. Data on a blockchain is collected and organized into blocks. Blocks are linked together and protected using cryptography. Blockchain perfectly complements large-scale IoT with its inherently enhanced interoperability, security, privacy, reliability, and scalability. Therefore, blockchain technology offers several features, such as interoperability between devices, traceability of large amounts of data, autonomous interaction with other IoT systems, and the massive connectivity stability of 6G communication systems.

[0174] 3D networking

[0175] 6G systems integrate terrestrial and airborne networks to support vertically expanded user communications. 3D BS will be provided via low-orbit satellites and UAVs. Adding a new dimension in altitude and associated degrees of freedom, 3D connections differ significantly from existing 2D networks.

[0176] Quantum communication

[0177] Unsupervised reinforcement learning holds promise in the context of 6G networks. Supervised learning approaches cannot label the massive amounts of data generated by 6G networks. Unsupervised learning does not require labeling. Therefore, this technology can be used to autonomously build representations of complex networks. Combining reinforcement learning and unsupervised learning allows for truly autonomous network operation.

[0178] drone

[0179] Unmanned Aerial Vehicles (UAVs), or drones, will be a key element in 6G wireless communications. In most cases, high-speed wireless connections will be provided using UAV technology. BS entities are installed on UAVs to provide cellular connectivity. UAVs offer specific capabilities not found in fixed BS infrastructure, such as easy deployment, robust line-of-sight links, and controlled mobility. During emergencies such as natural disasters, deploying terrestrial communication infrastructure is not economically feasible, and sometimes, volatile environments make it impossible to provide services. UAVs can easily handle these situations. UAVs will become a new paradigm in wireless communications. This technology facilitates three fundamental requirements for wireless networks: enhanced mobile broadband (eMBB), URLLC, and mMTC. UAVs can also support various purposes, such as enhancing network connectivity, fire detection, disaster emergency services, security and surveillance, pollution monitoring, parking monitoring, and accident monitoring. Therefore, UAV technology is recognized as one of the most important technologies for 6G communications.

[0180] Cell-free Communication

[0181] Tight integration of multiple frequencies and heterogeneous communication technologies is crucial in 6G systems. As a result, users will be able to seamlessly move from one network to another without requiring any manual configuration on their devices. The best network will be automatically selected from available communication technologies. This will break the limitations of the cell concept in wireless communications. Currently, user movement from one cell to another in dense networks results in excessive handovers, resulting in handover failures, handover delays, data loss, and a ping-pong effect. 6G cell-free communications will overcome all of these challenges and provide better QoS. Cell-free communications will be achieved through multi-connectivity and multi-tier hybrid technologies, as well as heterogeneous radios on devices.

[0182] Integration of wireless information and energy transmission

[0183] WIET uses the same fields and waves as wireless communication systems. Specifically, sensors and smartphones will be charged using wireless power transfer during communication. WIET is a promising technology for extending the life of battery-powered wireless systems. Therefore, battery-less devices will be supported by 6G communications.

[0184] Integration of sensing and communication

[0185] Autonomous wireless networks are capable of continuously sensing dynamically changing environmental conditions and exchanging information between different nodes. In 6G, sensing will be tightly integrated with communications to support autonomous systems.

[0186] Integration of Access Backhaul Networks

[0187] In 6G, the density of access networks will be enormous. Each access network will be connected to backhaul connections, such as fiber optics and FSO networks. To accommodate the massive number of access networks, there will be tight integration between access and backhaul networks.

[0188] Holographic beam forming

[0189] Beamforming is a signal processing procedure that adjusts an antenna array to transmit a wireless signal in a specific direction. It is a subset of smart antennas or advanced antenna systems. Beamforming technology offers several advantages, including high signal-to-noise ratio, interference avoidance and rejection, and high network efficiency. Holographic beamforming (HBF) is a novel beamforming method that differs significantly from MIMO systems because it uses software-defined antennas. HBF will be a highly effective approach for efficient and flexible signal transmission and reception in multi-antenna communication devices in 6G.

[0190] Big data analysis

[0191] Big data analytics is a complex process for analyzing diverse, large-scale data sets, or "big data." This process uncovers hidden data, unknown correlations, and customer trends, ensuring complete data management. Big data is collected from various sources, such as video, social networks, images, and sensors. This technology is widely used to process massive amounts of data in 6G systems.

[0192] Large Intelligent Surface (LIS)

[0193] THz-band signals have strong linearity, which can create many shadow areas due to obstacles. LIS technology, which enables expanded communication coverage, enhanced communication stability, and additional value-added services by installing LIS near these shadow areas, is becoming increasingly important. LIS is an artificial surface made of electromagnetic materials that can alter the propagation of incoming and outgoing radio waves. While LIS can be viewed as an extension of massive MIMO, it differs from massive MIMO in its array structure and operating mechanism. Furthermore, LIS operates as a reconfigurable reflector with passive elements, passively reflecting signals without using active RF chains, which offers the advantage of low power consumption. Furthermore, because each passive reflector in LIS must independently adjust the phase shift of the incoming signal, this can be advantageous for wireless communication channels. By appropriately adjusting the phase shift via the LIS controller, the reflected signal can be collected at the target receiver to boost the received signal power.

[0194]

[0195] Terahertz (THz) wireless communications in general

[0196] THz wireless communication is a wireless communication using THz waves with a frequency of approximately 0.1 to 10 THz (1 THz = 10^12 Hz). It can 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 light, they penetrate non-metallic / non-polarizable materials well, and compared to RF / millimeter waves, they have a shorter wavelength, so they have high linearity and can focus beams. In addition, since the photon energy of THz waves is only a few meV, they have the characteristic of being harmless to the human body. The frequency bands expected to be used for THz wireless communication may be the D-band (110 GHz to 170 GHz) or H-band (220 GHz to 325 GHz), which have low propagation loss due to molecular absorption in the air. Discussions on standardization of THz wireless communication are being centered around the IEEE 802.15 THz working group in addition to 3GPP, and standard documents issued by the IEEE 802.15 Task Group (TG3d, TG3e) may specify or supplement the contents described in various embodiments of the present disclosure. THz wireless communication can be applied to wireless cognition, sensing, imaging, wireless communication, THz navigation, etc.

[0197] Figure 7 is a diagram illustrating an example of a THz communication application.

[0198] As illustrated in Figure 7, THz wireless communication scenarios can be categorized into macro networks, micro networks, and nanoscale networks. In macro networks, THz wireless communication can be applied to vehicle-to-vehicle and backhaul / fronthaul connections. In micro networks, THz wireless communication can be applied to fixed point-to-point or multi-point connections, such as indoor small cells, wireless connections in data centers, and near-field communications, such as kiosk downloads.

[0199] Table 2 below shows examples of technologies that can be used in THz waves.

[0200] Transceivers DeviceAvailable immature: UTC-PD, RTD and SBDModulation and CodingLow order modulation techniques (OOK, QPSK), LDPC, Reed Soloman, Hamming, Polar, TurboAntennaOmni and Directional, phased array with low number of antenna elementsBandwidth69GHz (or 23 GHz) at 300GHzChannel modelsPartiallyData rate100GbpsOutdoor deploymentNoFree space lossHighCoverageLowRadio Measurements300GHz indoorDevice sizeFew micrometers

[0201] THz wireless communications can be categorized based on the methods used to generate and receive THz waves. THz generation methods can be categorized as either optical or electronic-based.

[0202] Fig. 8 is a diagram illustrating an example of an electronic component-based THz wireless communication transmitter and receiver.

[0203] Methods for generating THz using electronic components include a method using semiconductor components such as a resonant tunneling diode (RTD), a method using a local oscillator and a multiplier, a MMIC (Monolithic Microwave Integrated Circuits) method using an integrated circuit based on a compound semiconductor HEMT (High Electron Mobility Transistor), and a method using a Si-CMOS-based integrated circuit. In the case of Fig. 15, a multiplier (doubler, tripler, multiplier) is applied to increase the frequency, and it passes through a subharmonic mixer and is radiated by an antenna. Since the THz band forms a high frequency, a multiplier is essential. Here, the multiplier is a circuit that has an output frequency that is N times that of the input, and matches it to the desired harmonic frequency and filters out all remaining frequencies. In addition, beamforming can be implemented by applying an array antenna or the like to the antenna of Fig. 8. In Fig. 8, IF represents intermediate frequency, tripler and multiplexer represent multipliers, PA represents a power amplifier, LNA represents a low noise amplifier, and PLL represents a phase-locked loop.

[0204] FIG. 9 is a diagram illustrating an example of a method for generating a THz signal based on an optical element.

[0205] Fig. 10 is a diagram illustrating an example of an optical element-based THz wireless communication transceiver.

[0206] Optical component-based THz wireless communication technology refers to a method of generating and modulating THz signals using optical components. Optical component-based THz signal generation technology generates an ultra-high-speed optical signal using a laser and an optical modulator, and converts it into a THz signal using an ultra-high-speed photodetector. Compared to technologies that use only electronic components, this technology can easily increase the frequency, generate high-power signals, and obtain flat response characteristics over a wide frequency band. As illustrated in Figure 16, optical component-based THz signal generation requires a laser diode, a wideband optical modulator, and an ultra-high-speed photodetector. In the case of Figure 16, the light signals of two lasers with different wavelengths are combined to generate a THz signal corresponding to the wavelength difference between the lasers. In Fig. 9, an optical coupler refers to a semiconductor device that transmits an electrical signal using optical waves to provide electrical isolation and coupling between circuits or systems, and a UTC-PD (Uni-Travelling Carrier Photo-Detector) is a type of photodetector that uses electrons as active carriers and reduces the travel time of electrons with bandgap grading. The UTC-PD is capable of detecting light at 150 GHz or higher. In Fig. 10, an EDFA (Erbium-Doped Fiber Amplifier) ​​represents an erbium-doped fiber amplifier, a PD (Photo Detector) represents a semiconductor device that can convert an optical signal into an electrical signal, an OSA represents an optical module (Optical Sub Assembly) that modularizes various optical communication functions (photoelectric conversion, electro-optical conversion, etc.) into a single component, and a DSO represents a digital storage oscilloscope.

[0207] The structure of a photoelectric converter (or photoelectric converter) is described with reference to FIGS. 11 and 12.

[0208] Fig. 11 is a diagram illustrating the structure of a photon source-based transmitter.

[0209] Figure 12 is a drawing showing the structure of an optical modulator.

[0210] In general, the phase of a signal can be changed by passing the optical source of a laser through an optical wave guide. At this time, data is loaded by changing the electrical characteristics through a microwave contact, etc. Therefore, the optical modulator output is formed as a modulated waveform. An opto-electrical modulator (O / E converter) can generate THz pulses by optical rectification operation by a nonlinear crystal, photoelectric conversion by a photoconductive antenna, emission from a bunch of relativistic electrons, etc. Terahertz pulses generated in the above manner can have a length in units of femtoseconds to picoseconds. An optical / electronic converter (O / E converter) performs down conversion by utilizing the non-linearity of the device.

[0211] Considering the THz spectrum usage, it is likely that THz systems will use multiple contiguous gigahertz bands for fixed or mobile service purposes. Based on the outdoor scenario criteria, the available bandwidth can be classified based on the oxygen attenuation of 10^2 dB / km in the spectrum up to 1 THz. Accordingly, a framework in which the available bandwidth is composed of multiple band chunks can be considered. As an example of the above framework, if the THz pulse length for one carrier is set to 50 ps, ​​the bandwidth (BW) becomes approximately 20 GHz.

[0212] Effective down-conversion from the infrared band (IR band) to the terahertz band (THz band) depends on how to utilize the nonlinearity of the optical / electrical converter (O / E converter). In other words, to down-convert to the desired terahertz band (THz band), it is necessary to design an optical / electrical converter (O / E converter) with the most ideal non-linearity for transferring to the corresponding terahertz band (THz band). If an optical / electrical converter (O / E converter) that is not suitable for the target frequency band is used, errors are likely to occur in the amplitude and phase of the corresponding pulse.

[0213] In a single-carrier system, a terahertz transmission and reception system can be implemented using a single optical-to-electrical converter. Depending on the channel environment, in a multi-carrier system, the number of optical-to-electrical converters may be equal to the number of carriers. This phenomenon will be particularly noticeable in a multi-carrier system that utilizes multiple broadbands according to the aforementioned spectrum usage plan. In this regard, a frame structure for the multi-carrier system may be considered. A signal down-converted using an optical-to-electrical converter may be transmitted in a specific resource region (e.g., a specific frame). The frequency region of the specific resource region may include multiple chunks. Each chunk may be composed of at least one component carrier (CC).

[0214]

[0215] Specific description of various embodiments of the present disclosure

[0216] Hereinafter, various embodiments of the present disclosure will be described in more detail.

[0217] In high-frequency communications, increasing transmit power may be required to overcome path attenuation. An example of a factor limiting power increase in OFDM-based wireless communication systems is the peak-to-average ratio (PAPR). In conventional communication systems, multiple subcarrier signals are merged and transmitted in the time domain. This results in time-domain signals with higher transmit power than the average transmit power. This peak value of these signals can hinder overall transmission power increase.

[0218] To address these issues, many precoder-based PAPR reduction algorithms have been proposed. For example, one algorithm was proposed to divide a transmitted OFDM symbol into subbands and apply (multiply) a precoder to each subband to reduce the overall PAPR. However, these techniques require the transmission of the precoder value for each OFDM symbol, which can increase complexity.

[0219] The present disclosure proposes a signal transmission and reception method capable of reducing PAPR without precoder transmission by transmitting a pilot signal or reference signal having a structure similar to a conventional PTRS (Phase Tracking Reference Signal) for each sub-band or sub-block. The present disclosure also proposes a PAPR precoder generation method to reduce complexity.

[0220] FIG. 13 is a drawing for explaining a reference signal structure to which the present disclosure can be applied.

[0221] Fig. 13 illustrates a conventional reference signal structure. According to Fig. 13, a conventional OFDM symbol may include a PTRS for phase noise (PN) and a DMRS / CSI-RS for channel estimation.

[0222] Conventional MIMO precoder estimation can be performed simultaneously with channel estimation via DMRS, considering that the channel remains constant over time. However, because the PAPR precoder uses different values ​​for each OFDM symbol, it cannot be estimated using reference signals such as DMRS, as is the case with MIMO precoders, which use the same precoder over a period of time. For this reason, conventional precoder transmission occurred along with data for each symbol.

[0223] In particular, in multi-user environments, the need to transmit a PAPR precoder set of values ​​for each user can increase overhead. Furthermore, increasing the precoder quantization level to improve PAPR performance can lead to overhead issues due to the increased precoder data volume.

[0224] To address these issues, the present disclosure proposes a reference signal structure for improving PAPR and an OFDM signal structure for estimating a PAPR precoder at the receiver. Furthermore, the present disclosure proposes a Multi-Purpose Reference Signal (MPRS) for estimating PAPR at the transmitter. The MPRS can be transmitted for each subband of each OFDM symbol, and the receiver can perform precoder estimation using the MPRS for each OFDM symbol.

[0225]

[0226] Referring to FIGS. 14 to 31 below, a signal transmission and reception method according to the present disclosure will be described in detail.

[0227] FIG. 14 is a diagram illustrating an example of a reference signal transmission structure according to the present disclosure, and FIG. 15 is a diagram for explaining the performance of a reference signal according to the present disclosure.

[0228] Referring to FIG. 14, the reference signal transmission structure according to the present disclosure may include multiple sub-bands and may include at least one MPRS.

[0229] Referring to Figure 15, PAPR reduction performance can vary depending on the number of subbands (M). For example, as M increases, the complexity of generating a PAPR precoder can significantly increase. The present disclosure proposes an adaptive precoder algorithm for estimating a target PAPR.

[0230] Since communication performance can be maintained constant only when PAPR is constant, fixing the PAPR value can improve communication system performance. Referring to Fig. 15, maintaining PAPR = 7.5 dB satisfies 70% data when M = 4, and M = 8 can be used to satisfy 20% data, and M = 16 can be used to satisfy 9% data. In order to achieve PAPR below 7.5 dB, M = 16 was fixed in the past, but in the present disclosure, M = 4, 8, and 16 can be used adaptively.

[0231] FIG. 16 is another drawing illustrating an example of a reference signal transmission structure according to the present disclosure.

[0232] Fig. 16 illustrates a reference signal structure according to the present disclosure. In Fig. 16, the reference signal transmission structure excluding MPRS may be identical to a conventional signal transmission structure.

[0233] For example, MPRS may have the same structure as PTRS. One or more MPRSs may be placed per subband of each symbol. MPRSs may be used to estimate PAPR precoder at the receiver. Since MPRSs have the same structure as PTRSs, they may be used to estimate CPE (Common Phase Error) for PNs and may also be used to directly estimate PNs. The name MPRS is merely an example, and the reference signal according to the present disclosure may be named with various names having functions described below.

[0234] FIG. 17 is a drawing for explaining a signal transmission method according to the present disclosure.

[0235] FIG. 17 illustrates a structural diagram of a transmitter according to the present disclosure. According to FIG. 17, the transmitter can map data and various reference signals to subcarriers and input them to a PAPR precoder block. The signals input to the precoder block can be grouped into M subbands to generate a precoder corresponding to each subband. The generated M precoders can form a PAPR mitigation matrix, which is an orthogonal matrix. The PAPR mitigation matrix can be multiplied by an input signal to generate a final transmission signal.

[0236] FIG. 18 is another drawing for explaining a signal transmission method according to the present disclosure.

[0237] The structural diagram of Fig. 18 is similar to the structural diagram of Fig. 17, but illustrates an example in which Discrete Fourier Transform spread OFDM (DFT-s-OFDM) is utilized for data mapping. The present disclosure can also be applied to DFT-s-OFDM used in general uplink.

[0238] Below, we describe the method for deriving the PAPR mitigation matrix.

[0239] FIG. 19 is a diagram for explaining an OFDM symbol according to the present disclosure.

[0240] Fig. 19 illustrates an OFDM symbol to which the present disclosure is applied. At this time, DMRS and PTRS may not be multiplied by a PAPR precoder.

[0241] FIG. 20 is a diagram for explaining a sub-band signal configuration according to the present disclosure.

[0242] The mathematical expression in Fig. 20 represents the structure of a sub-band containing PTRS. In the mathematical expression, represents the m-th sub-band data of the k-th symbol, and P MP,mrepresents the MPRS of the m-th subband, and P DM,m can represent the DMRS of the mth sub-block. At this time, PTRS and DMRS have a precoder q k,m This may not be multiplied. This can be confirmed in the determinant where only PTRS and MPRS are multiplied by 1. PTRS and DMRS are used for CPE and channel estimation, respectively, and if they are multiplied by a PAPR precoder, CPE and channel estimation may become difficult.

[0243] FIG. 21 is another diagram for explaining a sub-band signal configuration according to the present disclosure.

[0244] The mathematical formula in Fig. 21 represents the structure of a sub-band in which PTRS does not exist. In the mathematical formula in Fig. 21, all signals except the DMRS portion can be multiplied by the PARR precoder.

[0245] Figure 22 is a drawing for explaining a mitigation matrix according to the present disclosure.

[0246] Figure 22 shows the overall precoder mitigation matrix ( ) is shown. The mathematical formula represents the input signal of the mth subband of the kth symbol, Is It can be a zero matrix of size 0.

[0247] Below, we describe a method for deriving an adaptive PAPR precoder.

[0248] FIG. 23 is another diagram for explaining the performance of a reference signal according to the present disclosure.

[0249] Figure 23 illustrates the performance change of the present disclosure according to the size M of the sub-band. The PAPR value varies depending on the input data, and the performance for PAPR can be expressed in the form of a statistical numerical value, CCDF (Complementary cumulative distribution function) (1-PDF (Probability Density Function)).

[0250] For example, the CCDF indicating PAPR = 8 dB based on M = 4 is 0.01, which can mean that the probability of data having a PAPR of 8 dB or less is 99%.

[0251] From the perspective of a transmit power amplifier, the maximum output power must be limited by the peak value, so a PAPR of 8 dB could mean that the average output power is 8 dB lower than the maximum output power. Since signal quality is determined by the average output power, a lower PAPR can lead to higher average power. Therefore, a constant PAPR value can be advantageous for maintaining signal quality.

[0252] FIG. 24 is a diagram illustrating an example of a reference signal generation method according to the present disclosure.

[0253] Figure 24 illustrates an adaptive PAPR precoder generation method proposed by the present disclosure. When there are at most M (e.g., M = 16) subbands, a PAPR precoder can be estimated based on a minimum unit (e.g., 4). In the example of Figure 24, the same precoder can be applied to groups of 4 for each of the 16 subbands. After applying the precoder, if the PAPR is calculated and the target PAPR threshold is not satisfied, four precoders can be added to change the subband size to 8. In this case, the four precoder values ​​derived previously can be used as is, or four new precoders can be derived. In this way, M precoders can be recursively derived.

[0254] Below, the channel estimation method of the receiver is described.

[0255] FIG. 25 is a drawing for explaining a signal receiving method according to the present disclosure.

[0256] Figure 25 illustrates a receiver structure for receiving a reference signal according to the present disclosure. The receiver can perform CPE and channel estimation using PTRS and DMRS. Since the PTRS and DMRS are not multiplied by a PAPR precoder at the transmitter, the receiver can perform CPE and channel estimation according to a conventional method. The following mathematical expression 1 expresses channel estimation assuming complete removal of CPE.

[0257] [Mathematical Formula 1]

[0258]

[0259] In mathematical expression 1, represents a signal consisting only of DMRS of the kth symbol, and P DM represents the DMRS matrix.

[0260] Below, we describe how the receiver estimates the PAPR precoder.

[0261] The mathematical expression 2 below estimates the channel using DMRS and then uses the PAPR precoder. It is a formula that expresses the method of estimating .

[0262] [Equation 2]

[0263]

[0264] Here represents a set of subcarrier transmission signals including DMRS, and P MP is a value known as DMRS value, and H k can represent the estimated channel value.

[0265] FIG. 26 is another diagram for explaining the performance of a reference signal according to the present disclosure.

[0266] Figure 26 illustrates the performance results of the adaptive PAPR precoder derivation method proposed in this disclosure. The results of the proposed method are depicted by the dotted lines in Figure 26, which indicate a circle. These results may be achieved by setting the target PAPR to 7.5 dB. Referring to Figure 26, it can be confirmed that the performance of the present disclosure satisfies the 7.5 dB or lower limit in most cases.

[0267] The reduction in complexity of the present disclosure compared to the exhausted precoder estimation method is estimated as follows. If the number of precoder candidates is B and M sub-bands are used, the complexity is B. M It can be. In a simulation environment where M = 16, the case where M = 4 is 70%, the case where M = 8 (when precoders are derived twice by 4 each) is 20%, and the remaining case is M = 16 (when precoders are derived four times by 4 each), so the complexity reduction ratio can be expressed as the following mathematical expression 3.

[0268] [Equation 3]

[0269]

[0270] FIG. 27 is another diagram for comparing the performance of reference signals according to the present disclosure.

[0271] While conventional methods apply a PAPR precoder to the entire data set, the proposed method does not apply a PAPR precoder to DMRS and PTRS. Therefore, the proposed method may exhibit worse PAPR performance compared to conventional methods that use a full precoder.

[0272] Figure 27 illustrates simulation results for a case where the FFT size is 1024 and the subband size is 8. Since only one MPRS is typically required per subband, there is little difference in performance compared to using the entire data set. However, when the number of MPRSs exceeds two, a slight performance difference can be observed. In the present disclosure, one MPRS is used per subband, so it can be seen that the present disclosure exhibits little performance degradation compared to conventional methods.

[0273] FIG. 28 is a drawing for explaining a data loading method according to the present disclosure, and FIG. 29 is a drawing for explaining the performance of the data loading method according to the present disclosure.

[0274] In general, performance differences can be significant when data from a subcarrier is not fully utilized, but rather only a portion of the subcarriers. Specifically, for uplink transmission, a terminal can only utilize a portion of the base station's subcarriers. Figure 29 illustrates PAPR performance when configuring a data load, as in Figure 28, and applying DFT-s-OFDM for uplink use.

[0275] Referring to Figure 29, it can be confirmed that when the proposed method is applied to DFT-s-OFDM, which is effective in reducing PAPR, PAPR performance is further improved. According to Figure 29, it can be confirmed that the system performance is further improved in uplink situations with low data load.

[0276] FIG. 30 is a diagram illustrating an example of a method for a first node to transmit and receive a signal in a system applicable to the present disclosure.

[0277] The embodiments described below are specifically described with reference to FIG. 30 in terms of terminal operation. The methods described below are distinguished for convenience of explanation, and it is understood that, unless mutually exclusive, some components of one method may be substituted for or combined with some components of another method.

[0278] In the following description, the first node and the second node may represent at least one of a transmitter, a receiver, a terminal, and a base station. For example, the first node may represent a transmitter, and the second node may represent a receiver.

[0279] Referring to FIG. 30, a method performed by a first node in a communication system includes a step of generating a transmission signal including transmission data and at least one reference signal (S3010), a step of dividing the transmission signal into a plurality of sub-bands (S3020), a step of deriving a precoder for the transmission signal based on the plurality of sub-bands (S3030), a step of applying the precoder to the transmission signal (S3040), and a step of transmitting the transmission signal to a second node (S3050), wherein the at least one reference signal may include a first reference signal used to estimate the precoder in the second node.

[0280] According to various embodiments of the present disclosure, the first reference signal may be included in at least one symbol constituting the sub-band.

[0281] According to various embodiments of the present disclosure, the precoder can be derived for each of the plurality of sub-bands.

[0282] According to various embodiments of the present disclosure, the step of applying the precoder to the transmission signal may include the step of generating a mitigation matrix using the precoder and the step of applying the mitigation matrix to the transmission signal.

[0283] According to various embodiments of the present disclosure, the step of deriving the precoder may include the step of estimating the precoder based on the number of the plurality of sub-bands, the step of estimating a peak-to-average power ratio (PAPR) of the transmission signal based on the precoder, and the step of deriving the precoder based on whether the estimated PAPR exceeds a preset PAPR.

[0284] According to various embodiments of the present disclosure, based on the estimated PAPR not exceeding the preset PAPR, the precoder can be derived as an estimated precoder based on the number of the plurality of sub-bands.

[0285] According to various embodiments of the present disclosure, based on the estimated PAPR exceeding the preset PAPR, the precoder can be derived based on a precoder that is recursively estimated based on the number of sub-bands into which the plurality of sub-bands are recursively divided.

[0286] According to various embodiments of the present disclosure, the plurality of sub-bands can be recursively divided based on multiples of a preset number.

[0287] According to various embodiments of the present disclosure, the at least one reference signal includes at least one of a Demodulation Reference Signal (DMRS) and a Phase Tracking Reference Signal (PTRS), wherein the precoder may not be applied to the DMRS and PTRS.

[0288] According to various embodiments of the present disclosure, the transmission signal may not include the derived precoder.

[0289] According to various embodiments of the present disclosure, a first node may be provided in a communication system. The terminal may include a transceiver and at least one processor, wherein the at least one processor may be configured to perform the operating method of the first node according to FIG. 30.

[0290] According to various embodiments of the present disclosure, a device for controlling a first node in a communication system may be provided. The device may include at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing an operating method of the first node according to FIG. 30 based on instructions executed by the at least one processor.

[0291] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media (CRM) storing one or more instructions may be provided. The one or more instructions, when executed by one or more processors, perform operations, and the operations may include the operating method of the first node according to FIG. 30.

[0292] FIG. 31 is a diagram illustrating an example of a method for a second node to transmit and receive signals in a system applicable to the present disclosure.

[0293] The embodiments described below are specifically described in terms of terminal operation with reference to FIG. 31. The methods described below are distinguished for convenience of explanation, and it is understood that, unless mutually exclusive, some components of one method may be substituted for or combined with some components of another method.

[0294] Referring to FIG. 31, a method performed by a second node in a communication system may include a step of receiving a transmission signal including data and at least one reference signal from a first node (S3110), a step of performing channel estimation based on the transmission signal (S3120), a step of estimating a precoder for the transmission signal based on the transmission signal and the channel (S3130), and a step of obtaining data included in the transmission signal based on the channel and the precoder (S3140).

[0295] According to various embodiments of the present disclosure, the at least one reference signal includes a Demodulation Reference Signal (DMRS), and the channel can be estimated based on the DMRS.

[0296] According to various embodiments of the present disclosure, the at least one reference signal may include a first reference signal used to estimate the precoder.

[0297] According to various embodiments of the present disclosure, the precoder can be estimated based on at least one of the channel, the DMRS, and the first reference signal.

[0298] According to various embodiments of the present disclosure, a base station may be provided in a communication system. The base station may include a transceiver and at least one processor, wherein the at least one processor may be configured to perform the operating method of a second node according to FIG. 31.

[0299] According to various embodiments of the present disclosure, a device for controlling a base station in a communication system may be provided. The device may include at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing the operating method of a second node according to FIG. 31 based on instructions executed by the at least one processor.

[0300] According to various embodiments of the present disclosure, one or more non-transitory computer-readable media (CRM) storing one or more instructions may be provided. The one or more instructions, when executed by one or more processors, perform operations, and the operations may include the operating method of a second node according to FIG. 31.

[0301]

[0302] Communication system applicable to the present disclosure

[0303] FIG. 32 illustrates a communication system (1) applicable to various embodiments of the present disclosure.

[0304] Referring to FIG. 32, a communication system (1) applied to various embodiments of 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 (New RAT), LTE (Long Term Evolution), 6G wireless communication), and may be referred to as a communication / wireless / 5G device / 6G 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 device / server (400). 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 vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. Mobile devices may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. Home appliances may include a TV, a refrigerator, a washing machine, etc. IoT devices may include a sensor, a smart meter, etc. For example, a base station and a network may also be implemented as a wireless device, and a specific wireless device (200a) may act as a base station / network node to other wireless devices.

[0305] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). Artificial Intelligence (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 (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, or a 6G network. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station / network. 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 (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0306] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base stations (200), and base stations (200) / base stations (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and base station-to-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, 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.), and resource allocation processes can be performed based on various proposals of various embodiments of the present disclosure.

[0307] Meanwhile, NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, an SCS of 15 kHz supports a wide area in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0308] The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values ​​of the frequency ranges can be changed, and for example, the frequency ranges of the two types (FR1, FR2) can be as shown in Table 3 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 can mean the "sub 6 GHz range", and FR2 can mean the "above 6 GHz range" and can be called millimeter wave (mmW).

[0309] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1450MHz-6000MHz15, 30, 60kHzFR224250MHz-52600MHz60, 120, 240kHz

[0310] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band from 410 MHz to 7125 MHz, as shown in Table 4 below. That is, FR1 may include a frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, such as for vehicular communications (e.g., autonomous driving).

[0311] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR141MHz-7125MHz15, 30, 60kHzFR224250MHz-52600MHz60, 120, 240kHz

[0312] According to various embodiments of the present disclosure, the communication system (1) can support terahertz (THz) wireless communication. THz wireless communication is a wireless communication using THz waves having a frequency of approximately 0.1 to 10 THz (1 THz = 10^12 Hz), and may refer to terahertz (THz) band wireless communication using a very high carrier frequency of 100 GHz or higher. The frequency band expected to be used for THz wireless communication may be a D-band (110 GHz to 170 GHz) or H-band (220 GHz to 325 GHz) band where propagation loss due to absorption of molecules in the air is small.

[0313]

[0314] Wireless devices applicable to the present disclosure

[0315] Below, examples of wireless devices to which various embodiments of the present disclosure are applied are described.

[0316] FIG. 33 illustrates a wireless device that can be applied to various embodiments of the present disclosure.

[0317] Referring to FIG. 33, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the base station (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 32.

[0318] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). In addition, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In various embodiments of the present disclosure, a wireless device may mean a communication modem / circuit / chip.

[0319] The second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In various embodiments of the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0320] Hereinafter, the hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) 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 operation flowcharts disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) can 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 (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0321] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) 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 (102, 202). 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 (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). 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.

[0322] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0323] One or more transceivers (106, 206) 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 (106, 206) 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 (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) 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 (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0324] FIG. 34 illustrates another example of a wireless device that can be applied to various embodiments of the present disclosure.

[0325] According to FIG. 34, the wireless device may include at least one processor (102, 202), at least one memory (104, 204), at least one transceiver (106, 206), and one or more antennas (108, 208).

[0326] The difference between the example of the wireless device described in FIG. 33 and the example of the wireless device in FIG. 34 is that in FIG. 33, the processor (102, 202) and the memory (104, 204) are separated, but in the example of FIG. 34, the memory (104, 204) is included in the processor (102, 202).

[0327] Here, the specific description of the processor (102, 202), memory (104, 204), transceiver (106, 206), and one or more antennas (108, 208) is as described above, so in order to avoid unnecessary repetition of description, the description of the repeated description is omitted.

[0328] Below, examples of signal processing circuits to which various embodiments of the present disclosure are applied are described.

[0329] Figure 35 illustrates a signal processing circuit for a transmission signal.

[0330] Referring to FIG. 35, the signal processing circuit (1000) may include a scrambler (1010), a modulator (1020), a layer mapper (1030), a precoder (1040), a resource mapper (1050), and a signal generator (1060). Although not limited thereto, the operations / functions of FIG. 35 may be performed in the processor (102, 202) and / or the transceiver (106, 206) of FIG. 33. The hardware elements of FIG. 35 may be implemented in the processor (102, 202) and / or the transceiver (106, 206) of FIG. 33. For example, blocks 1010 to 1060 may be implemented in the processor (102, 202) of FIG. 33. Additionally, blocks 1010 to 1050 may be implemented in the processor (102, 202) of FIG. 33, and block 1060 may be implemented in the transceiver (106, 206) of FIG. 33.

[0331] The codeword can be converted into a wireless signal through the signal processing circuit (1000) of FIG. 35. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transport block (e.g., an UL-SCH transport block, a DL-SCH transport block). The wireless signal may be transmitted through various physical channels (e.g., a PUSCH or a PDSCH).

[0332] Specifically, the codeword can be converted into a bit sequence scrambled by a scrambler (1010). 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 (1020). The modulation method may include pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying), m-QAM (m-Quadrature Amplitude Modulation), etc. The complex modulation symbol sequence can be mapped to one or more transmission layers by a layer mapper (1030). The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (1040) (precoding). The output z of the precoder (1040) can be obtained by multiplying the output y of the layer mapper (1030) by a precoding matrix W of N*M. Here, N is the number of antenna ports, and M is the number of transmission layers. Here, the precoder (1040) can perform precoding after performing transform precoding (e.g., DFT transform) on complex modulation symbols. In addition, the precoder (1040) can perform precoding without performing transform precoding.

[0333] The resource mapper (1050) 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 (1060) 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 (1060) can include an Inverse Fast Fourier Transform (IFFT) module, a Cyclic Prefix (CP) inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0334] The signal processing process for receiving signals in a wireless device can be configured in reverse order of the signal processing process (1010 to 1060) of FIG. 42. For example, a wireless device (e.g., 100, 200 of FIG. 40) 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.

[0335] Below, examples of wireless device utilization to which various embodiments of the present disclosure are applied are described.

[0336] Figure 36 illustrates another example of a wireless device applicable to various embodiments of the present disclosure. The wireless device may be implemented in various forms depending on the use case / service.

[0337] Referring to FIG. 36, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 40 and may be composed of various elements, components, units / units, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and a transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 40. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 40. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0338] The additional element (140) may be configured in various ways depending on the type of the wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 32, 100a), a vehicle (Fig. 32, 100b-1, 100b-2), an XR device (Fig. 32, 100c), a portable device (Fig. 32, 100d), a home appliance (Fig. 32, 100e), an IoT device (Fig. 32, 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. 32, 400), a base station (Fig. 32, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0339] In FIG. 36, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and a first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of a set of one or more processors. For example, the control unit (120) 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 (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0340] The claims described in the various embodiments of the present disclosure may be combined in various ways. For example, the technical features of the method claims of the various embodiments of the present disclosure may be combined and implemented as a device, and the technical features of the device claims of the various embodiments of the present disclosure may be combined and implemented as a method. Furthermore, the technical features of the method claims of the various embodiments of the present disclosure may be combined and implemented as a device, and the technical features of the method claims of the various embodiments of the present disclosure may be combined and implemented as a method.

Claims

1. In a method performed by a first node in a communication system, A step of generating a transmission signal including transmission data and at least one reference signal; A step of dividing the above transmission signal into a plurality of sub-bands; A step of deriving a precoder for the transmission signal based on the plurality of sub-bands; a step of applying the precoder to the transmission signal; and Including a step of transmitting the above transmission signal to a second node, A method wherein said at least one reference signal comprises a first reference signal used to estimate said precoder at said second node.

2. In paragraph 1, A method wherein the first reference signal is included in at least one symbol constituting the sub-band.

3. In paragraph 1, The above precoder is a method in which each of the plurality of sub-bands is derived.

4. In paragraph 1, The step of applying the above precoder to the above transmission signal is: A step of generating a mitigation matrix using the above precoder; and A method comprising the step of applying the mitigation matrix to the transmission signal.

5. In paragraph 1, The step of deriving the above precoder is: A step of estimating a precoder based on the number of the plurality of sub-bands; A step of estimating the PAPR (Peak-to-Average Power Ratio) of the transmission signal based on the precoder; and A method comprising a step of deriving the precoder based on whether the estimated PAPR exceeds a preset PAPR.

6. In paragraph 5, A method in which the precoder is derived as an estimated precoder based on the number of the plurality of sub-bands, based on the fact that the estimated PAPR does not exceed the preset PAPR.

7. In paragraph 5, A method in which the precoder is derived based on a precoder that is recursively estimated based on the number of subbands into which the plurality of subbands are recursively divided, based on the fact that the estimated PAPR exceeds the preset PAPR.

8. In paragraph 7, A method in which the above plurality of sub-bands are recursively divided based on multiples of a preset number.

9. In paragraph 1, The at least one reference signal includes at least one of a DMRS (Demodulation Reference Signal) and a PTRS (Phase Tracking Reference Signal), The above precoder is not applicable to the DMRS and PTRS.

10. In paragraph 1, A method wherein the above transmission signal does not include the above derived precoder.

11. In a method performed by a second node in a communication system, A step of receiving a transmission signal including data and at least one reference signal from a first node; A step of performing channel estimation based on the above transmission signal; A step of estimating a precoder for the transmission signal based on the transmission signal and the channel; and A method comprising the step of obtaining data included in the transmission signal based on the channel and the precoder.

12. In paragraph 11, A method wherein at least one reference signal includes a Demodulation Reference Signal (DMRS), and the channel is estimated based on the DMRS.

13. In paragraph 11, A method wherein said at least one reference signal comprises a first reference signal used to estimate said precoder.

14. In paragraph 13, A method wherein the precoder is estimated based on at least one of the channel, the DMRS and the first reference signal.

15. In a first node operating in a communication system, Transmitter and receiver; at least one processor; and At least one memory operably connectable to said at least one processor and storing instructions that, when executed by said at least one processor, perform operations; The above actions are, A first node comprising all steps of a method according to any one of claims 1 to 10.

16. In a second node operating in a communication system, Transmitter and receiver; at least one processor; and At least one memory operably connectable to said at least one processor and storing instructions that, when executed by said at least one processor, perform operations; The above actions are, A second node comprising all steps of the method according to any one of claims 11 to 14.

17. In a control device that controls a first node in a communication system, at least one processor; and comprising at least one memory operably connected to at least one of the processors; The at least one memory stores instructions for performing operations based on being executed by the at least one processor, The above actions are, A control device comprising all steps of a method according to any one of claims 1 to 10.

18. In a control device that controls a second node in a communication system, at least one processor; and comprising at least one memory operably connected to at least one of the processors; The at least one memory stores instructions for performing operations based on being executed by the at least one processor, The above actions are, A control device comprising all steps of a method according to any one of claims 10 to 14.

19. In one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions perform operations based on being executed by one or more processors, The above actions are, Comprising all steps of the method according to any one of claims 1 to 10, Computer readable medium.

20. In one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions perform operations based on being executed by one or more processors, The above actions are, A computer-readable medium comprising all steps of a method according to any one of claims 11 to 14.

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