Method and apparatus for successive nonlinear interference cancellation in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. Specifically, according to various embodiments of the present disclosure, a method performed by a receiving device in a wireless communication system comprises the steps of: receiving a plurality of data packets from at least one transmitting device; decoding a first data packet from among the plurality of data packets; recovering the first data packet that has been decoded, on the basis of a reception signal quality of a second data packet from among the plurality of data packets and a reception signal quality of the decoded first data packet; and removing the recovered first data packet from the plurality of data packets.

Description

Method and device for sequential nonlinear interference cancellation in wireless communication systems

[0001] The present disclosure relates generally to wireless communication systems, and more particularly to devices and methods for sequentially removing nonlinear interference in wireless communication systems.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of the 5G (5th Generation) communication system, an explosive increase in connected devices is expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction equipment, and factory equipment. Mobile devices are also expected to evolve into diverse form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th Generation) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "beyond 5G."

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes (i.e., 1,000 gigabits) per second (bps) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster and the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz (THz) band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to have more severe path loss and atmospheric absorption, making it more important to develop technologies that can guarantee signal reach, or coverage. Key technologies to ensure coverage include Radio Frequency (RF) components, antennas, new waveforms that offer better coverage than Orthogonal Frequency Division Multiplexing (OFDM), beamforming, and multiple antenna transmission technologies such as massive Multiple-Input and Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources at the same time for uplink and downlink; network technology that integrates satellites and HAPS (High-Altitude Platform Stations); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (Artificial Intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (Mobile Edge Computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable services such as truly immersive eXtended Reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems through enhanced security and reliability, will be applied in diverse fields such as industry, medicine, automobiles, and home appliances.

[0007] Meanwhile, to expand coverage, power amplifiers (PAs) are being used to generate higher output power. However, this can lead to nonlinearity, which distorts the transmitted signal in the high-power range of the PA. Therefore, a method is needed to improve nonlinearity without reducing coverage or requiring backoff.

[0008] Various embodiments of the present disclosure are intended to provide a device and method capable of effectively providing a service in a wireless communication system.

[0009] According to various embodiments of the present disclosure, a method performed by a receiving device in a wireless communication system includes the steps of receiving a plurality of data packets from at least one transmitting device, decoding a first data packet among the plurality of data packets, reconstructing the decoded first data packet based on a reception signal quality of a second data packet among the plurality of data packets and a reception signal quality of the decoded first data packet, and canceling the reconstructed first data packet from the plurality of data packets, wherein the decoding may be performed based on information about a nonlinearity between the at least one transmitting device and the receiving device.

[0010] According to various embodiments of the present disclosure, a receiving device of a wireless communication system comprises a transceiver, and at least one control unit connected to the transceiver, wherein the at least one control unit is configured to receive a plurality of data packets from at least one transmitting device, decode a first data packet among the plurality of data packets, reconstruct the decoded first data packet based on a reception signal quality of a second data packet among the plurality of data packets and a reception signal quality of the decoded first data packet, and cancel the reconstructed first data packet from the plurality of data packets, wherein the decoding may be performed based on information about a nonlinearity between the at least one transmitting device and the receiving device.

[0011] Various embodiments of the present disclosure aim to provide devices and methods capable of effectively providing services in a wireless communication system. More specifically, according to various embodiments of the present disclosure, transmission signal distortion due to nonlinearity can be improved without backoff while ensuring transmission signal coverage.

[0012] Additionally, the receiving device can adaptively operate according to the communication environment by applying different interference cancellation methods by taking into account both the complexity and nonlinearity of the signal processing procedure.

[0013] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0014] FIG. 1 illustrates an example of a wireless communication environment according to embodiments of the present disclosure.

[0015] FIG. 2 illustrates an example of a configuration of a base station in a wireless communication system according to embodiments of the present disclosure.

[0016] FIG. 3 illustrates an example of a configuration of a terminal in a wireless communication system according to embodiments of the present disclosure.

[0017] FIG. 4a illustrates an example of nonlinearity of a power amplifier in accordance with embodiments of the present disclosure.

[0018] FIG. 4b illustrates an example of signal distortion of a power amplifier in accordance with embodiments of the present disclosure.

[0019] FIG. 5 illustrates an example of nonlinearity compensation in accordance with embodiments of the present disclosure.

[0020] FIG. 6a illustrates an example of BER (bit error ratio) performance according to a receiver according to embodiments of the present disclosure.

[0021] FIG. 6b illustrates a block diagram of successive interference cancellation (SIC) in accordance with embodiments of the present disclosure.

[0022] FIG. 7 illustrates an example of BER performance according to a receiver in the presence of nonlinearity in accordance with embodiments of the present disclosure.

[0023] FIG. 8 illustrates an example of a block diagram of successive nonlinear interference cancellation (SNIC) according to embodiments of the present disclosure.

[0024] FIG. 9 illustrates an example of a block diagram of a SNIC according to embodiments of the present disclosure.

[0025] FIG. 10 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0026] FIG. 11 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0027] FIG. 12 illustrates an example of MU-MIMO (multi-user multiple input & multiple output) according to embodiments of the present disclosure.

[0028] FIG. 13 illustrates an example of SU-MIMO (single-user multiple input & multiple output) according to embodiments of the present disclosure.

[0029] FIG. 14 illustrates the relationship between modulation and coding scheme (MCS) and error vector magnitude (EVM) according to embodiments of the present disclosure.

[0030] FIG. 15 illustrates the relationship between MCS and EVM limits according to embodiments of the present disclosure.

[0031] FIG. 16 illustrates an example of a signal processing procedure according to embodiments of the present disclosure.

[0032] FIG. 17 illustrates an example of a signal processing procedure in a first stage according to embodiments of the present disclosure.

[0033] FIG. 18 illustrates an example of a signal processing procedure in a second stage according to embodiments of the present disclosure.

[0034] FIG. 19 illustrates an example of a signal processing procedure in a third stage according to embodiments of the present disclosure.

[0035] FIG. 20 illustrates an example of a signal processing procedure in the fourth stage according to embodiments of the present disclosure.

[0036] FIG. 21 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0037] FIG. 22 illustrates the BER performance of a receiver when non-linearity compensation (NC) is applied according to embodiments of the present disclosure.

[0038] In connection with the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0039] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0040] The various embodiments of the present disclosure described below illustrate a hardware-based approach as an example. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0041] In the following description, terms referring to components of the device (control unit, processor, artificial intelligence (AI) model, encoder, decoder, autoencoder (AE), neural network (NN) model, etc.) and terms referring to data (signal, feedback, report, reporting, information, parameter, value, bit, codeword, etc.) are examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having similar or equivalent technical meanings may be used.

[0042] Additionally, while this disclosure describes various embodiments using terminology used in certain communication standards (e.g., 3rd Generation Partnership Project (3GPP)), these are merely illustrative examples. The various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0043] FIG. 1 illustrates a wireless communication system according to various embodiments of the present disclosure. FIG. 1 illustrates a base station (110), a terminal (120), and a terminal (130) as some of the nodes utilizing a wireless channel in the wireless communication system. While FIG. 1 illustrates only one base station, other base stations identical to or similar to base station (110) may be included.

[0044] The base station (110) is a network infrastructure that provides wireless access to terminals (120, 130). The base station (110) has coverage defined as a certain geographical area based on the distance at which a signal can be transmitted. In addition to the base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', 'gNodeB (gNB)', '5th generation node', '6th generation node', 'wireless point', 'transmission / reception point (TRP)', or other terms having equivalent technical meanings.

[0045] Each of the terminals (120) and (130) is a device used by a user and communicates with the base station (110) via a wireless channel. In some cases, at least one of the terminals (120) and (130) may be operated without the user's intervention. That is, at least one of the terminals (120) and (130) is a device that performs machine type communication (MTC) and may not be carried by the user. Each of the terminal (120) and the terminal (130) may be referred to as a 'terminal', 'user equipment (UE),' 'mobile station,' 'subscriber station,' 'customer premises equipment (CPE),' 'remote terminal,' 'wireless terminal,' 'electronic device,' or 'user device,' or other terms having similar or equivalent technical meanings thereto.

[0046] The base station (110), the terminal (120), and the terminal (130) can transmit and receive wireless signals in the millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz, over 60 GHz, etc.). At this time, in order to improve the channel gain, the base station (110), the terminal (120), and the terminal (130) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. That is, the base station (110), the terminal (120), and the terminal (130) can provide directionality to the transmission signal or the reception signal. To this end, the base station (110) and the terminals (120, 130) can select serving beams (112, 113, 121, 131) through a beam search or beam management procedure. After serving beams (112, 113, 121, 131) are selected, subsequent communication can be performed through resources that are in a QCL (quasi co-located) relationship with the resources that transmitted the serving beams (112, 113, 121, 131).

[0047] FIG. 2 illustrates an example of a configuration of a base station in a wireless communication system according to embodiments of the present disclosure. According to various embodiments of the present disclosure, the base station (110) may be conveniently referred to as a network. The configuration illustrated in FIG. 2 can be understood as the configuration of the base station (110). Terms such as "unit" and "unit" used hereinafter mean a unit that processes at least one function or operation, and this can be implemented by hardware, software, or a combination of hardware and software.

[0048] Referring to FIG. 2, the base station (110) may include a wireless communication unit (210), a backhaul communication unit (220), a storage unit (230), and a control unit (240).

[0049] The wireless communication unit (210) performs functions for transmitting and receiving signals through a wireless channel. For example, the wireless communication unit (210) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the wireless communication unit (210) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the wireless communication unit (210) restores a reception bit stream by demodulating and decoding a baseband signal. In addition, the wireless communication unit (210) upconverts a baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and downconverts an RF band signal received through the antenna into a baseband signal.

[0050] To this end, the wireless communication unit (210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In addition, the wireless communication unit (210) may include a plurality of transmission and reception paths. Furthermore, the wireless communication unit (210) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the wireless communication unit (210) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units according to operating power, operating frequency, etc.

[0051] The wireless communication unit (210) can transmit and receive signals. To this end, the wireless communication unit (210) may include at least one transceiver. For example, the wireless communication unit (210) may transmit a synchronization signal, a reference signal, system information, messages, control information, or data. In addition, the wireless communication unit (210) may perform beamforming.

[0052] The wireless communication unit (210) transmits and receives signals as described above. Accordingly, all or part of the wireless communication unit (210) may be referred to as a "transmitter," a "receiver," or a "transmitting and receiving unit." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean processing performed by the wireless communication unit (210) as described above.

[0053] The backhaul communication unit (220) provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (220) converts a bit string transmitted from the base station (110) to another node, such as another access node, another base station, an upper node, a core network, etc., into a physical signal, and converts a physical signal received from another node into a bit string.

[0054] The storage unit (230) stores data such as basic programs, application programs, and setting information for the operation of the base station (110). The storage unit (230) may include a memory. The storage unit (230) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the storage unit (230) may provide stored data upon request from the control unit (240).

[0055] The control unit (240) controls the overall operations of the base station (110). For example, the control unit (240) transmits and receives signals through the wireless communication unit (210) or the backhaul communication unit (220). In addition, the control unit (240) records and reads data from the storage unit (230). In addition, the control unit (240) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (240) can include at least one processor.

[0056] Although not illustrated in FIG. 2, the base station (110) may further include a receiving device that performs embodiments of the present disclosure according to various embodiments of the present disclosure. Specifically, the receiving device may be included in the wireless communication unit (210), or may be included in the base station (110) separately from the wireless communication unit (210). Alternatively, the receiving device may be located outside the base station (110) and may be connected to the base station (110) wirelessly or by wire. In this case, the receiving device may include at least one receiver. In addition, the control unit (240) may control the receiving device to perform the embodiments of the present disclosure below.

[0057] The configuration of the base station (110) illustrated in FIG. 2 is merely an example of a base station, and examples of base stations that perform various embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 2. That is, some configurations may be added, deleted, or changed according to various embodiments.

[0058] Although the base station is described as a single entity in FIG. 2, the present disclosure is not limited thereto. The base station according to various embodiments of the present disclosure may be implemented to form an access network having not only an integrated deployment but also a distributed deployment. According to one embodiment, the base station may be divided into a central unit (CU) and a digital unit (DU), and the CU may be implemented to perform upper layer functions (e.g., radio link control (RLC), packet data convergence protocol (PDCP), and radio resource control (RRC)) and the DU may be implemented to perform lower layer functions (e.g., medium access control (MAC), physical (PHY)). The DU of the base station may form beam coverage on a wireless channel.

[0059] FIG. 3 illustrates an example of a configuration of a terminal in a wireless communication system according to embodiments of the present disclosure. The configuration illustrated in FIG. 3 can be understood as a configuration of terminals (120, 130). Terms such as "unit" and "unit" used hereinafter refer to a unit that processes at least one function or operation, and can be implemented using hardware, software, or a combination of hardware and software.

[0060] Referring to FIG. 3, the terminal (120, 130) may include a communication unit (310), a storage unit (320), and a control unit (330).

[0061] The communication unit (310) performs functions for transmitting and receiving signals via a wireless channel. For example, the communication unit (310) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (310) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the communication unit (310) restores a reception bit stream by demodulating and decoding the baseband signal. In addition, the communication unit (310) upconverts a baseband signal to an RF band signal and transmits it through an antenna, and downconverts an RF band signal received through the antenna to a baseband signal. For example, the communication unit (310) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0062] In addition, the communication unit (310) may include a plurality of transmission and reception paths. Furthermore, the communication unit (310) may include an antenna unit. The communication unit (310) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (310) may be composed of digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). Here, the digital circuits and analog circuits may be implemented in a single package. In addition, the communication unit (310) may include a plurality of RF chains. The communication unit (310) may perform beamforming. The communication unit (310) may apply beamforming weights to a signal to be transmitted and received in order to impart directionality according to the settings of the control unit (330). According to one embodiment, the communication unit (310) may include an RF (radio frequency) block (or RF unit). The RF block may include first RF circuitry associated with the antenna and second RF circuitry associated with baseband processing. The first RF circuitry may be referred to as RF-A (antenna). The second RF circuitry may be referred to as RF-B (baseband).

[0063] In addition, the communication unit (310) can transmit and receive signals. For this purpose, the communication unit (310) can include at least one transceiver. The communication unit (310) can receive a downlink signal. The downlink signal can include a synchronization signal (SS), a reference signal (RS) (e.g., demodulation (DM)-RS), system information (e.g., master information block (MIB), system information block (SIB), remaining system information (RMSI), other system information (OSI)), a configuration message, control information, or downlink data. In addition, the communication unit (310) can transmit an uplink signal. The uplink signal may include a random access related signal (e.g., a random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), a reference signal (e.g., a sounding reference signal (SRS), DM-RS), or a power headroom report (PHR).

[0064] Additionally, the communication unit (310) may include different communication modules to process signals of different frequency bands. Furthermore, the communication unit (310) may include multiple communication modules to support multiple different wireless access technologies. For example, different wireless access technologies may include Bluetooth low energy (BLE), wireless fidelity (Wi-Fi), WiGig (WiFi gigabyte), cellular networks (e.g., long term evolution (LTE), new radio (NR), etc.). In addition, different frequency bands may include super high frequency (SHF) (e.g., 2.5 GHz, 5 GHz) bands, millimeter wave (mm wave) (e.g., 38 GHz, 60 GHz, etc.) bands. In addition, the communication unit (310) may use the same type of wireless access technology on different frequency bands (e.g., unlicensed bands for licensed assisted access (LAA), citizens broadband radio service (CBRS) (e.g., 3.5 GHz)).

[0065] The communication unit (310) transmits and receives signals as described above. Accordingly, all or part of the communication unit (310) may be referred to as a "transmitter," a "receiver," or a "transmitting and receiving unit." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean processing performed by the communication unit (310) as described above.

[0066] The storage unit (320) stores data such as basic programs, application programs, and setting information for the operation of the terminal (120). The storage unit (320) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the storage unit (320) may provide stored data upon request from the control unit (330).

[0067] The control unit (330) controls the overall operations of the terminals (120, 130). For example, the control unit (330) transmits and receives signals through the communication unit (310). In addition, the control unit (330) records and reads data in the storage unit (320). In addition, the control unit (330) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (330) may include at least one processor. The control unit (330) may include at least one processor or microprocessor, or may be a part of a processor. In addition, a part of the communication unit (310) and the control unit (330) may be referred to as a CP (cellular processor). The control unit (330) may include various modules for performing communication. According to various embodiments, the control unit (330) may control the terminal to perform operations according to various embodiments.

[0068] Although not illustrated in FIG. 3, the terminal (120, 130) according to various embodiments of the present disclosure may further include a receiving device that performs embodiments of the present disclosure. Specifically, the receiving device may be included in the communication unit (310) or may be included in the terminal (120, 130) separately from the communication unit (310). Alternatively, the receiving device may be located outside the terminal (120, 130) and may be wirelessly connected to the terminal (120, 130). In this case, the receiving device may include at least one receiver. In addition, the control unit (330) may control the receiving device to perform the embodiments of the present disclosure below.

[0069] The configuration of the terminals (120, 130) illustrated in FIG. 3 is merely an example of a terminal, and examples of terminals performing various embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 3. That is, some configurations may be added, deleted, or changed according to various embodiments.

[0070] Meanwhile, in the embodiments of the present disclosure below, the operations of the receiving device may be performed by incorporating artificial intelligence (AI) technology. For example, the receiving device may be capable of learning through an AI model. A supervised learning method may be used to train an AI model by providing ground truth values ​​and learning the ground truth values ​​as labeling values ​​for training data. Alternatively, an unsupervised learning method may be used to train an AI model by extracting relationships and characteristics between data without ground truth values. Furthermore, a reinforcement learning method may be used to train an AI model through a reward system. Among the aforementioned AI model learning methods, supervised learning makes it difficult to collect labeled data, but can train an AI model with good performance. AI models can be trained offline, using a well-trained model from the outset, or online, where the model is continuously updated to reflect the ever-changing environment. Offline training can eliminate the need for further training once the AI ​​model is trained on a large data set, when no changes are required. For example, during the chip design process, an AI model can be pre-trained and then integrated into the chip's algorithm.However, in cases where the environment is constantly changing, it is difficult for a fixed AI model to reflect the changing environment, so an online training method in which the AI ​​model is continuously updated may be a more appropriate method.

[0071] Hereinafter, in the embodiments of the present disclosure, the operations of the receiving device to secure coverage while improving nonlinearity may be performed by the AI ​​model described above. Accordingly, the nonlinearity compensation method using the AI ​​model may also be referred to as AI-NC technology.

[0072] FIG. 4a illustrates an example of nonlinearity of a power amplifier in accordance with embodiments of the present disclosure.

[0073] Referring to Fig. 4a, the distortion of the transmitted signal due to the nonlinear characteristics of the high-power region of the PA can be explained. First, various technologies have been proposed to expand coverage. For example, a method of transmitting a signal at a higher output power by utilizing a power amplifier (PA) may be possible. However, the use of the PA at high power levels may be limited due to nonlinearity in the high-power region of the PA, which distorts the phase and magnitude of the transmitted signal. For example, due to the nonlinear characteristics, the output power may not be uniformly amplified depending on the input power, and the actual output of the amplified signal may decrease. Therefore, to avoid operation in the nonlinear region, a back-off process may be performed that limits the operating range of the PA to an output lower than the maximum output power. When the back-off is applied, the probability of the PA input signal being included in the nonlinear region is reduced, which can improve the deterioration of data reception performance due to nonlinearity. However, relatively low transmission power can lead to reduced coverage (e.g., coverage loss). To address these issues, peak-to-average power ratio (PAPR) reduction technologies, digital pre-distortion (DPD) technologies, and NC technologies are being discussed. Furthermore, discussions are ongoing on how to utilize artificial intelligence (AI) to address nonlinearities.

[0074] FIG. 4b illustrates an example of signal distortion of a power amplifier in accordance with embodiments of the present disclosure.

[0075] Referring to Fig. 4b, the distortion of a time domain (TD) signal after applying a PA can be explained. In addition, the error vector magnitude (EVM) before and after applying a PA can be explained. For example, in the time domain, a transmitted signal may experience signal distortion after applying a PA. In particular, the greater the transmission power of the transmitted signal, the greater the degree of signal distortion. For example, in the constellation diagram, the EVM of a signal after applying a PA may not be ideal compared to the signal before applying the PA.

[0076] Accordingly, the present disclosure may describe methods for resolving nonlinearity issues arising from the application of a PA to a transmission signal. Specifically, methods for removing nonlinear characteristics while a receiving device restores a transmission signal that has passed through a PA may be described. In one embodiment, NC, successive interference cancellation (hereinafter SIC), and successive nonlinear interference cancellation (hereinafter SNIC) may be proposed as methods for removing nonlinear characteristics. In one embodiment, a method for determining whether to apply at least one of the above-described methods for removing nonlinear characteristics depending on a communication environment may be proposed.

[0077] FIG. 5 illustrates an example of nonlinearity compensation in accordance with embodiments of the present disclosure.

[0078] Referring to Fig. 5, a block diagram of a receiver for compensating for nonlinearity (hereinafter, referred to as an NC receiver) may be described. For example, the NC receiver may be a receiver further including an NC block that performs an NC operation. The NC receiver may further perform the NC operation in the process of demodulating symbols in each subcarrier through a fast Fourier transform (FFT) algorithm after removing a CP (cyclic prefix).

[0079] More specifically, the NC receiver can remove the CP from the received signal and then convert the signal in the time domain into a signal in the frequency domain (FD) through an FFT algorithm. The NC receiver can filter the transmitted signal through a pre-EQ (equalizer). The received signal after the pre-EQ (e.g., the received OFDM) may have a reduced output compared to the transmitted signal before the PA is applied. At this time, the pre-EQ may include frequency domain channel estimation (FD CE) and FD EQ. Thereafter, the NC receiver can convert the signal in the frequency domain back into a signal in the time domain through an inverse fast Fourier transform (IFFT).

[0080] In one embodiment, the NC receiver can compensate for nonlinearity of data symbols in a time domain signal (e.g., a received signal after pre-EQ) through an NC operation. For example, the NC receiver can obtain information about nonlinearity through a reference signal (RS) (e.g., including at least one of a demodulation reference signal (DMRS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a sounding reference signal (SRS), or a channel state information reference signal (CSI-RS)). The NC receiver can compensate for nonlinearity of data symbols based on the obtained information about nonlinearity. At this time, the nonlinearity information can include information about a characteristic of a reference signal commonly known to a transmitting device and a receiving device that is distorted due to nonlinearity during a transmission process. For example, the NC receiver can compensate for nonlinearity of a received signal by inversely reflecting in the received signal the characteristic of the reference signal being distorted during the transmission process.

[0081] Therefore, the received signal after NC (e.g., the received signal after AI-NC) may be closer to the transmitted signal before PA than the received signal before NC. The NC receiver can perform demodulation and channel decoding (or decoding) on ​​the received signal after NC by performing FFT again.

[0082] FIG. 6a illustrates an example of BER performance according to a receiver according to embodiments of the present disclosure.

[0083] Referring to FIG. 6a, a graph is shown showing bit error rate (BER) performance according to the type of receiver under specific conditions (e.g., TDL (tapped delay line)-C channel, 4Rx, 3UEs, 1024-DFT (discrete Fourier transform), 300REs (resource elements), and 256QAM (quadrature amplitude modulation)).

[0084] For example, in a signal-to-noise ratio (SNR)-BER graph of receivers that each include zero-forcing (ZF), SIC, and ordered successive interference cancellation (OSIC) operations, a receiver that performs the OSIC operation may have the lowest error rate. In this case, OSIC may be a method in which packets with high channel power are sequentially decoded. In embodiments of the present disclosure, a packet is a data processing unit and may be received through different layers in single-user multiple input & multiple output (SU-MIMO) or multi-user multiple input & multiple output (MU-MIMO).

[0085] At this time, when the receiving device receives multiple data signals that are transmitted by sharing frequency, time, and / or space by overlapping them, the receiving device can decode some of the received signals. In addition, the receiving device can restore the original signal by utilizing the decoded data packets. In addition, the receiving device can apply SIC, which repeatedly performs a process of sequentially removing the restored signal from the received signal. A unit of a bundle of data signals to be sequentially decoded may be referred to as a 'packet'. In addition, a series of processes of removing the decoded and restored packets for each packet from the original signal may be referred to as a 'stage'. Therefore, SIC may be a method of repeatedly performing stages proportional to the number of overlapped packets. Ordered-SIC (OSIC), which performs SIC by determining the order in consideration of the channel conditions experienced by each packet, may be a method for minimizing the error propagation problem in which an error occurring in a previous stage adversely affects the next stage in the process of removing the restored signal from the received signal. Therefore, in Fig. 6a, which shows performance according to the receiving technology, there may be a receiving performance gain when applying SIC or OSIC.

[0086] FIG. 6b illustrates a block diagram of an SIC related to embodiments of the present disclosure.

[0087] Referring to FIG. 6b, a block diagram of a receiver performing sequential interference cancellation (e.g., SIC) can be illustrated. The receiving device can improve reception performance by sequentially canceling co-channel interference that occurs when multiple signals are received via a common resource (e.g., a reference signal).

[0088] In one embodiment, the receiving device can decode the first packet from the received signal (Y). The receiving device can restore the received signal of the first packet by utilizing the decoded first packet (X_1). Then, the receiving device can cancel the received signal (X_1) of the first packet restored from the original signal (e.g., the initial received signal). The above-described procedures can be divided into one stage. Then, the receiving device can use the signal (Y_(1)) output from the first stage as the original signal in the stage for the second packet. Therefore, the receiving device can perform a successive interference cancellation method for canceling interference of a signal of a next stage based on a signal output from a previous stage. The receiving device can sequentially perform the above-described operations for each packet until all packets are decoded.

[0089] FIG. 7 illustrates an example of BER performance according to a receiver in the presence of nonlinearity in accordance with embodiments of the present disclosure.

[0090] Referring to Fig. 7, a graph is shown showing the BER performance according to the type of receiver under specific conditions (e.g., TDL-C channel, 4Rx, 3UEs, 1024-DFT, 300REs, 256QAM, PA with 3.5% EVM applied) when nonlinearity exists. Fig. 7 can show the reception performance when performing SIC, OSIC, and ZF in a situation where distorted signals due to nonlinear characteristics are received by sharing frequency, time, and space. For example, in Fig. 7, the cases without nonlinear characteristics and the cases when a PA with 3.5% EVM is applied can be compared in each of the receiving devices performing the OSIC, SIC, and ZF methods. In each of the receiving devices performing the OSIC, SIC, and ZF methods, the cases without nonlinear characteristics can have a lower BER at the same SNR compared to the cases where nonlinear characteristics are generated by applying a PA. Therefore, when PA is applied in various interference cancellation methods, reception performance may deteriorate due to the occurrence of nonlinear characteristics.

[0091] When a received signal that has experienced nonlinearity (e.g., a received signal with PA applied) passes through a SIC receiver, the reception performance may deteriorate due to the error between the actual received signal that has experienced nonlinearity and the signal restored using the decoded packet. If SIC is performed on a signal distorted due to nonlinearity without considering the nonlinearity, the reception performance may deteriorate due to the error propagation problem between the actual received signal that has experienced nonlinearity and the signal restored using the decoded packet as the stage is repeated. In particular, when applying OSIC, the error propagation problem may be aggravated, further deteriorating the reception performance. To alleviate the error propagation problem, it is necessary to improve the error propagation problem by accurately restoring the signal by taking into account the nonlinearity experienced by the decoded data packet at each stage when restoring the original signal.

[0092] Embodiments of the present disclosure may include a signal restoration method that takes nonlinearity into account, so that when performing SIC or OSIC, accurate signals can be restored and removed at each stage in a situation where signals distorted due to nonlinearity are received by sharing frequency, time, and space, thereby mitigating error propagation problems. Accordingly, unlike existing SIC or OSIC reception technologies, the reception device can obtain nonlinearity information applied to the data signal at each stage, and additionally perform a process of restoring the signal using the obtained nonlinearity information. Furthermore, the reception device can perform NC at each stage to improve performance when decoding the data signal at each stage.

[0093] FIG. 8 illustrates an example of a block diagram of a SNIC according to embodiments of the present disclosure.

[0094] Referring to FIG. 8, a block diagram of a first stage in a receiving device performing a SNIC operation can be illustrated. When the receiving device receives a plurality of data signals that are transmitted by sharing frequency, time, and space by overlapping them, the receiving device can apply SIC, which repeatedly performs a process of decoding a portion of the received signals and restoring and removing the original signal from the received signals by utilizing the decoded data packets, and OSIC, which determines the decoding order to perform SIC for additional performance gains. At this time, in order to secure excellent reception performance while minimizing the error propagation problem for signals that have experienced distortion due to nonlinearity, the receiving device can perform SNIC, which performs decoding and restoration that takes nonlinearity information into account, when decoding a portion of the received signals and restoring the original signal by utilizing the decoded data packets.

[0095] In step 810, the receiving device can perform channel estimation for the received signal (Y). For example, the receiving device can estimate the channel status between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel can be expressed as follows. Therefore, the received signal can be expressed as in the following mathematical expression 1.

[0096]

[0097] At step 820, the receiving device may perform channel equalization using an equalizer based on the estimated channel information. For example, the receiving device may compensate for channel distortion in the received signal (Y). Specifically, channel equalization may be a process for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range.

[0098] At step 830, the receiving device decode the nonlinearity information experienced by the received signal from the received signal to be decoded in the first stage. ) can be obtained. The nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. In Fig. 8, the nonlinearity information acquisition block is illustrated after the channel equalization block of step 820, but is not limited thereto. Accordingly, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure.

[0099] In step 840, the receiving device can selectively perform NC according to the degree of nonlinearity experienced by the received signal when performing decoding on a portion of the received signal in the first stage. For example, the receiving device may obtain nonlinearity information ( ) can be reflected to determine whether to perform NC. Accordingly, if the receiving device determines to perform NC, an operation identical or similar to the NC in FIG. 5 described above can be performed.

[0100] At step 850, the receiving device can perform demodulation on the first packet that performed NC. Accordingly, the demodulated signal for the first packet (e.g., ) can be printed.

[0101] At step 860, the receiving device receives the demodulated signal for the first packet (e.g., ) can perform IDFT (inverse discrete Fourier transform).

[0102] At step 870, the receiving device decrypts the data packet (e.g., ) from nonlinearity information ( ) can be used to restore the original signal (e.g., the first packet). At this time, the decrypted data packet (e.g., ) from nonlinearity information ( ) to restore the original signal may be referred to as SNIC. Alternatively, the receiving device may decrypt the data packet (e.g., ) can also be used to restore the original signal without considering nonlinearity information. At this time, the decoded data packet (e.g., ) to restore the original signal without considering nonlinearity information can be referred to as SIC. The signal restored through SNIC can be expressed as in mathematical expression 2.

[0103]

[0104] And the receiving device can remove the restored original signal (e.g., Equation 2) from the received signal (Y), and can be expressed as Equation 3 below.

[0105]

[0106] In the above-described procedure, the restored k-th packet that the receiving device can obtain from the received signal and the received signal with the restored k-th packet removed can be expressed as in the following mathematical expressions 4 and 5, respectively.

[0107]

[0108]

[0109] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0110] FIG. 9 illustrates an example of a block diagram of a SNIC according to embodiments of the present disclosure.

[0111] Referring to Fig. 9, a block diagram of the first stage in a receiving device performing a SNIC operation can be shown. However, unlike the operation of Fig. 8 described above, the receiving device may be configured to receive nonlinearity information ( ) can be described, the operation of demodulating the first packet can be described. Therefore, the description overlapping with the above-described Fig. 8 can be omitted.

[0112] At step 910, the receiving device can perform channel estimation for the received signal (Y). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0113] At step 920, the receiving device may perform channel equalization using an equalizer based on the estimated channel information. For example, the receiving device may compensate for channel distortion in the received signal (Y). Specifically, channel equalization may be a process by which the receiving device ensures that the amplitude and phase characteristics are uniform across the entire frequency range.

[0114] At step 930, the receiving device decode the nonlinearity information experienced by the received signal from the received signal to be decoded in the first stage. ) can be obtained. The nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. In Fig. 9, the nonlinearity information acquisition block is illustrated after the channel equalization block of step 920, but is not limited thereto. Accordingly, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure.

[0115] In step 940, the receiving device can selectively perform NC according to the degree of nonlinearity experienced by the received signal when performing decoding on some of the received signals in the first stage. For example, the receiving device may obtain nonlinearity information ( ) can be used to determine whether to perform NC. Accordingly, if the receiving device determines not to perform NC, the receiving device can perform demodulation (e.g., 950 below) without performing NC after step 920.

[0116] At step 950, the receiving device can perform demodulation on the first packet that did not perform NC. Therefore, the demodulated signal for the first packet (e.g., ) can be printed.

[0117] At step 960, the receiving device receives the demodulated signal for the first packet (e.g., ) can perform IDFT.

[0118] At step 970, the receiving device may perform SNIC. For example, the receiving device may decrypt the data packet (e.g., ) from nonlinearity information ( ) can be taken into account to restore the original signal (e.g., the first packet). And the receiving device can remove the restored original signal from the received signal (Y).

[0119] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0120] FIG. 10 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0121] Referring to FIG. 10, the operation sequence from when the receiving device demodulates and restores one packet from the received signal in FIG. 8 or 9 described above to when the restored signal is removed from the received signal can be described.

[0122] In step 1010, the receiving device can perform channel estimation on the received signal. For example, the receiving device can estimate the channel conditions between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. Furthermore, the receiving device can perform channel equalization using an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion of the received signal. Specifically, channel equalization can be a process for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range.

[0123] At step 1020, the receiving device can obtain nonlinearity information experienced by the received signal from the received signal to be decoded at the stage. The nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may also perform the nonlinearity information acquisition procedure before the channel equalization procedure.

[0124] At step 1030, the receiving device may selectively perform NC based on the degree of nonlinearity experienced by the received signal during decoding of a portion of the received signal at that stage. For example, the receiving device may determine whether to perform NC based on the nonlinearity information acquired at step 1020.

[0125] In step 1040, the receiving device can perform demodulation and restoration on the packet for which NC was performed. When restoring the decoded data packet, the receiving device can determine whether to perform SIC or SNIC based on nonlinearity information. The receiving device can restore the packet according to the determined method. At this time, in the case of SNIC technology that considers nonlinearity, since it is necessary to acquire nonlinearity information and perform NC or signal restoration process using the acquired nonlinearity information, the complexity of the signal processing procedure may increase instead of obtaining improved reception performance. Therefore, through the selection operation of the continuous interference cancellation method in step 1040, the complexity may be reduced when the receiving device selects SIC, and the reception performance may be improved when the receiving device selects SNIC.

[0126] At step 1050, the receiving device can remove the restored signal from the original received signal according to the operation performed at step 1040 described above (e.g., SIC or SNIC).

[0127] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0128] FIG. 11 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0129] Referring to FIG. 11, the method for determining whether to perform NC in step 1030 of FIG. 10 described above and the method for selecting SIC / SNIC in step 1040 can be explained. Therefore, any explanation that overlaps with the explanation of FIG. 10 described above can be omitted.

[0130] At step 1110, when the receiving device receives a signal from the transmitting device, the receiving device may initialize n=0 for a portion of the received signal (e.g., the nth packet). For example, the receiving device may initialize n=0 for a packet for which restoration is to be performed in the first stage among the received signals.

[0131] At step 1120, the receiving device can set n=n+1 for the nth packet initialized with n=0. For example, the receiving device can set n=1 for the packet for which restoration is to be performed in the first stage among the received signals. Accordingly, the receiving device can perform a restoration procedure for the first packet in the first stage.

[0132] In step 1130, the receiving device can identify whether the received signal is a signal transmitted through multiple layers and whether n has a value greater than 1. At this time, a signal transmitted through multiple layers may mean receiving multiple data signals by overlapping them by sharing frequency, time, and / or space. For example, in the case of SU-MIMO, it may mean receiving multiple data signals by overlapping them from one transmitting device through multiple antennas. At this time, two or more packets included in the received signal may mean multiple data signals received from one transmitting device. Alternatively, in the case of MU-MIMO, it may mean receiving multiple data signals by overlapping them from multiple transmitting devices. For example, the nth packet may refer to the nth data signal received from the terminal. At this time, in the case of multi-layer transmission or when n is 1 (for example, when performing a restoration procedure for the first packet), step 1170 may be performed. At this time, two or more packets included in the received signal may refer to multiple data signals received from multiple transmitting devices. For example, the nth packet may refer to a data signal received from the nth terminal.

[0133] At step 1170, the receiving device detects nonlinearity information of the received signal ( ) and EVM limit (EVM limit value, or EVM threshold value) can be used to determine whether to perform NC. Hereinafter, in the embodiments of the present disclosure, EVM limit may be referred to as EVM threshold value. Specifically, the receiving device may compare the EVM threshold value for the first packet with the EVM value of the first packet considering nonlinearity. However, since the inequality in step 1170 is only one example, the case where the EVM value of the first packet considering nonlinearity is equal to the EVM threshold value for the first packet may be included. At this time, EVM is only one example of an index representing the quality of the received signal. Therefore, in addition to EVM, modulation error (MER), mean square error (MSE), or signal-to-noise ratio (SNR) may be used as an index to determine the quality of the received signal.

[0134] At step 1180, if the EVM value of the packet considering nonlinearity is greater than the EVM threshold for the packet, the receiving device may perform NC during decryption of the packet. For example, if the EVM value of the first packet considering nonlinearity is greater than the EVM threshold for the first packet, the receiving device may perform NC during decryption of the first packet to compensate for the nonlinearity.

[0135] At step 1190, after performing NC, the receiving device can determine whether the number of decrypted packets is equal to the total number of packets included in the received signal. For example, if the receiving device performed NC on the first packet, it can perform NC again from step 1120 described above.

[0136] At step 1140, if the transmission is multilayer and n is greater than 1, the receiving device can identify whether the signal quality (e.g., EVM value considering nonlinearity) of the (n-1)th packet is greater than the EVM threshold of the (n)th packet. For example, the receiving device can identify whether the signal quality (e.g., EVM value considering nonlinearity) of the first packet is greater than the EVM threshold of the (n)th packet. However, since the inequality at step 1140 is only one example, it may also include a case where the signal quality of the (n-1)th packet is equal to the EVM threshold of the (n)th packet.

[0137] In step 1150, if the signal quality (e.g., EVM value considering nonlinearity) of the (n-1)th packet is greater than the EVM threshold of the (n)th packet, the receiving device can perform SNIC. If the signal quality (e.g., EVM value considering nonlinearity) of the (n-1)th packet is greater than the EVM threshold of the (n)th packet, SNIC considering nonlinearity needs to be performed even if the complexity of the signal processing procedure increases because nonlinearity affects the receiving performance. For example, if the signal quality (e.g., EVM value considering nonlinearity) of the first packet is greater than the EVM threshold of the second packet, the receiving device can perform SNIC for the first packet considering nonlinearity. After performing step 1150, the receiving device can perform again from step 1170 described above.

[0138] In step 1160, if the signal quality (e.g., EVM value considering nonlinearity) of the (n-1)th packet is less than the EVM threshold of the (n)th packet, the receiving device may perform SIC. If the signal quality (e.g., EVM value considering nonlinearity) of the (n-1)th packet is less than or equal to the EVM threshold of the (n)th packet, SIC may need to be performed by considering the influence of the complexity of the signal processing procedure more than the influence of the nonlinearity. For example, if the signal quality (e.g., EVM value considering nonlinearity) of the first packet is less than the EVM threshold of the second packet, the receiving device may perform SIC on the first packet without considering the nonlinearity. After performing step 1160, the receiving device may perform again from step 1170 described above.

[0139] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0140] FIG. 12 illustrates an example of MU-MIMO according to embodiments of the present disclosure.

[0141] Referring to FIG. 12, a specific example of a method for determining whether a receiving device performs NC and selecting SIC / SNIC according to the operation sequence of FIG. 11 described above in an MU-MIMO environment is described. Therefore, any description overlapping with FIG. 11 may be omitted.

[0142] In one embodiment, in an MU-MIMO environment, superimposed data signals may be received from four transmitting devices (e.g., terminals). At this time, unlike the index of each transmitting device, each superimposed data signal included in the received signal may be ordered based on at least one of a channel condition and the quality of the received signal (e.g., reference signal received power (RSRP)). For example, the ordering may be sorted (or indexed) in order of increasing RSRP. In an embodiment of the present disclosure, a signal received from each transmitting device may be referred to as one packet. And the transmitting devices may have different modulation and coding schemes (MCS) and EVM threshold values. However, the EVM may be determined according to the form of the transmitted signal and / or the specifications of the PA. At this time, the EVM is only one example of an index representing the quality of the received signal. Therefore, in addition to EVM, MER, MSE, or SNR can also be used as indicators to judge the quality of the received signal.

[0143] For example, in the first stage, since the nonlinearity (-29 dB) of the first packet (e.g., the signal received through the first layer) is greater than the EVM threshold (-30 dB), the receiving device can perform NC by considering the nonlinearity. In addition, since the nonlinearity (-29 dB) of the first packet is less than the EVM threshold (-27 dB) of the second packet (e.g., the signal received through the second layer), the receiving device can perform SIC by considering the complexity of the signal processing procedure rather than the nonlinearity.

[0144] For example, in the second stage, since the nonlinearity (-28 dB) of the second packet is less than the EVM threshold (-27 dB), the receiving device may not perform NC. In addition, since the nonlinearity (-28 dB) of the second packet is less than the EVM threshold (-25 dB) of the third packet (e.g., the signal received through the third layer), the receiving device may perform SIC by considering the complexity of the signal processing procedure rather than the nonlinearity.

[0145] For example, in the third stage, since the nonlinearity (-24 dB) of the third packet is greater than the EVM threshold (-25 dB), the receiving device can perform NC considering the nonlinearity. In addition, since the nonlinearity (-24 dB) of the second packet is greater than the EVM threshold (-32 dB) of the fourth packet (e.g., the signal received through the fourth layer), the receiving device can perform SNIC considering the nonlinearity rather than the complexity of the signal processing procedure.

[0146] For example, in the 4th stage, since the nonlinearity (-31 dB) of the 4th packet is greater than the EVM threshold (-32 dB), the receiving device can perform NC by taking the nonlinearity into account.

[0147] Through the first to fourth stages described above, the packets of each stage can be decoded, and the packets of each stage are removed from the received signal at each stage and transmitted to the next stage, so that the receiving device can eliminate sequential nonlinear interference in an MU-MIMO environment. In addition, the receiving device can determine whether to perform NC according to the degree of nonlinearity. In addition, the receiving device can compare the degree of nonlinearity and the complexity of the signal processing procedure to determine which method to perform, SIC that does not consider nonlinearity or SNIC that considers nonlinearity. In addition, the embodiments of the present disclosure can be applied regardless of the modulation forms of the transmitted signal and the received signal, such as CP (cyclic prefix)-OFDM or DFT-s(spread)-OFDM. Of course, it is not limited to the above example, and is only an example of a signal processing procedure according to the operation sequence of FIG. 11 described above.

[0148] FIG. 13 illustrates an example of SU-MIMO according to embodiments of the present disclosure.

[0149] Referring to FIG. 13, a specific example of a method for determining whether a receiving device performs NC and selecting SIC / SNIC according to the operation sequence of FIG. 11 described above in a SU-MIMO environment is described. Therefore, any description overlapping with FIG. 11 may be omitted.

[0150] In one embodiment, superimposed data signals may be received from a transmitting device (e.g., a terminal) in a SU-MIMO environment. At this time, each of the superimposed data signals included in the received signal may be indexed based on at least one of a channel condition and the quality of the received signal (e.g., RSRP). For example, each data signal may be sorted (or indexed) in order of increasing RSRP. In an embodiment of the present disclosure, each of the data signals received from the transmitting device may be referred to as one packet. However, unlike in FIG. 12, since the data signals are received from a single transmitting device, the MCS and EVM threshold values ​​may both be the same. At this time, the EVM is only one example of an index representing the quality of the received signal. Therefore, in addition to the EVM, MER, MSE, or SNR may also be used as an index to determine the quality of the received signal. In addition, in the case of the EVM, a larger absolute value may indicate a smaller error, which may indicate better performance of the received signal.

[0151] For example, in the first stage, since the nonlinearity (-29 dB) of the first packet (e.g., the signal received through the first layer) is greater than the EVM threshold (-30 dB), the receiving device can perform NC considering the nonlinearity. In addition, since the nonlinearity (-29 dB) of the first packet is greater than the EVM threshold (-30 dB), the receiving device can perform SNIC considering the nonlinearity rather than the complexity of the signal processing procedure.

[0152] For example, in the second stage, since the nonlinearity (-31 dB) of the second packet (e.g., the signal received through the second layer) is less than the EVM threshold (-30 dB), the receiving device may not perform NC. In addition, since the nonlinearity (-31 dB) of the second packet is less than the EVM threshold (-30 dB), the receiving device may perform SIC by considering the complexity of the signal processing procedure rather than the nonlinearity.

[0153] For example, in the third stage, since the nonlinearity (-29 dB) of the third packet (e.g., the signal received through the third layer) is greater than the EVM threshold (-30 dB), the receiving device can perform NC considering the nonlinearity. In addition, since the nonlinearity (-24 dB) of the second packet is greater than the EVM threshold (-30 dB), the receiving device can perform SNIC considering the nonlinearity rather than the complexity of the signal processing procedure.

[0154] For example, in the 4th stage, the receiving device may not perform NC because the nonlinearity (-31 dB) of the 4th packet (e.g., the signal received through the 4th layer) is less than the EVM threshold (-30 dB).

[0155] Through the first to fourth stages described above, the packets of each stage can be decoded, and the packets of each stage are removed from the received signal at each stage and transmitted to the next stage, so that the receiving device can eliminate sequential nonlinear interference in a SU-MIMO environment. In addition, the receiving device can determine whether to perform NC according to the degree of nonlinearity. In addition, the receiving device can compare the degree of nonlinearity and the complexity of the signal processing procedure to determine which method to perform, SIC that does not consider nonlinearity or SNIC that considers nonlinearity. In addition, the embodiments of the present disclosure can be applied regardless of the modulation forms of the transmitted signal and the received signal, such as CP (cyclic prefix)-OFDM or DFT-s(spread)-OFDM. Of course, it is not limited to the above example, and is only an example of a signal processing procedure according to the operation sequence of FIG. 11 described above.

[0156] FIG. 14 illustrates the relationship between MCS and EVM according to embodiments of the present disclosure.

[0157] Referring to Figure 14, the EVM specifications related to 3GPP's 5G communication system are illustrated. As shown in the table, as modulation increases, lower EVM values ​​may be required. For example, for the physical downlink shared channel (PDSCH) of a 5G communication system, if the MCS is 256QAM, the EVM requirement may be 3.5% (or -29.12 dB).

[0158] Meanwhile, EVM can decrease as the measured symbol approaches the ideal symbol, as its magnitude decreases. Therefore, a lower EVM can indicate better signal quality. Conversely, a higher EVM can indicate poor signal quality, as the measured symbol moves further away from the ideal symbol.

[0159] FIG. 15 illustrates the relationship between MCS and EVM limits according to embodiments of the present disclosure.

[0160] Referring to Figure 15, the EVM specification is illustrated in a standard for WiFi (e.g., IEEE 802.11). For example, the relationship between MCS and the EVM threshold in 802.11 can be defined, and the higher the MCS, the smaller the EVM threshold. Therefore, the higher the MCS, the higher the demand for signal quality.

[0161] FIG. 16 illustrates an example of a signal processing procedure according to embodiments of the present disclosure.

[0162] Referring to FIG. 16, a block diagram is provided illustrating a signal processing procedure of the nth stage, including a method for determining whether a receiving device performs NC and selecting SIC / SNIC. While the following example describes a signal processing procedure in an MU-MIMO environment (e.g., FIG. 12 described above), it can also be applied to SU-MIMO (e.g., FIG. 13 described above).

[0163] At step 1610, the receiving device can perform channel estimation for the received signal (Y). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0164] In step 1620, the receiving device can perform channel equalization through an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion for the received signal (Y). Specifically, channel equalization can be a procedure for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range. In addition, the receiving device can obtain nonlinearity information () experienced by the received signal from the received signal to be decoded in the nth stage. ) can be obtained. Nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure. The receiving device may determine whether to perform NC by comparing the nonlinearity of the n-th packet (e.g., the received signal through the n-th layer) with an EVM threshold value. In one embodiment, when the nonlinearity of the n-th packet is greater than the EVM threshold value, the receiving device may identify that NC is performed by considering the nonlinearity. In one embodiment, when the nonlinearity of the n-th packet is less than the EVM threshold value, the receiving device may not perform NC.

[0165] At step 1630, if the receiving device identifies that it performs NC, the receiving device may perform IDFT for the n-th packet.

[0166] At step 1640, the receiving device can perform NC after performing IDFT. Specifically, the receiving device can perform nonlinearity information ( ) can be used to perform NC for the nth packet.

[0167] At step 1650, the receiving device can perform DFT after performing NC.

[0168] At step 1660, the receiving device can perform demodulation on the n-th packet for which NC has been performed. Therefore, the demodulated signal for the n-th packet (e.g., ) can be printed.

[0169] At step 1670, the receiving device receives the demodulated signal for the nth packet (e.g., ) can perform IDFT on the decrypted data packet (e.g., ) when restoring the original signal, nonlinearity information ( ) can be selected to be considered. In one embodiment, if the nonlinearity of the n-th packet is less than the EVM threshold of the n+1-th packet, the receiving device can be identified as performing SIC considering the complexity of the signal processing procedure rather than the nonlinearity. In one embodiment, if the nonlinearity of the n-th packet is greater than the EVM threshold of the n+1-th packet, the receiving device can be identified as performing SNIC considering the nonlinearity rather than the complexity of the signal processing procedure.

[0170] At step 1680, if the receiving device identifies that it is performing SNIC, the receiving device will receive nonlinearity information ( ) can be used to restore the nth packet. Alternatively, if the receiving device is identified as performing SIC, the receiving device can use the nonlinearity information ( ) can be used to restore the nth packet without considering the component. And the receiving device can remove the restored nth packet from the reception signal (Y), and the output signal (Y_(n)) with the component for the nth packet removed can be used as the reception signal in the next stage (n+1th stage).

[0171] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0172] FIG. 17 illustrates an example of a signal processing procedure in a first stage according to embodiments of the present disclosure.

[0173] Referring to FIG. 17, a block diagram is provided illustrating a signal processing procedure of the first stage, including a method for determining whether a receiving device performs NC and a method for selecting SIC / SNIC. While the following example describes a signal processing procedure in an MU-MIMO environment (e.g., FIG. 12 described above), it can also be applied to SU-MIMO (e.g., FIG. 13 described above).

[0174] At step 1710, the receiving device can perform channel estimation for the received signal (Y). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0175] In step 1720, the receiving device can perform channel equalization through an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion for the received signal (Y). Specifically, channel equalization can be a procedure for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range. In addition, the receiving device can decode the nonlinearity information () experienced by the received signal from the received signal to be decoded in the first stage. ) can be obtained. Nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure. The receiving device can determine whether to perform NC by comparing the nonlinearity of the first packet (e.g., the signal received through the first layer) and the EVM threshold value. At this time, since the nonlinearity (-29 dB) of the first packet (e.g., the signal received through the first layer) is greater than the EVM threshold value (-30 dB), the receiving device can identify that NC is performed by considering the nonlinearity.

[0176] At step 1730, if the receiving device identifies that it performs NC, the receiving device may perform IDFT on the first packet.

[0177] At step 1740, the receiving device can perform NC after performing IDFT. Specifically, the receiving device can perform NC using nonlinearity information (obtained before step 1730) ) can be used to perform NC on the first packet.

[0178] At step 1750, the receiving device can perform DFT after performing NC.

[0179] At step 1760, the receiving device can perform demodulation on the first packet that performed NC. Therefore, the demodulated signal for the first packet (e.g., ) can be printed.

[0180] At step 1770, the receiving device receives the demodulated signal for the first packet (e.g., ) can perform IDFT on the decrypted data packet (e.g., ) when restoring the original signal, nonlinearity information ( ) can be considered. At this time, since the nonlinearity (-29 dB) of the first packet is smaller than the EVM threshold (-27 dB) of the second packet (e.g., the signal received through the second layer), the receiving device can be identified as performing SIC by considering the complexity of the signal processing procedure rather than the nonlinearity.

[0181] At step 1780, if the receiving device identifies that it is performing SIC, the receiving device will receive nonlinearity information ( ) can be used to restore the first packet without considering the first packet. And the receiving device can remove the restored first packet from the reception signal (Y), and the output signal (Y_(1)) with the component for the first packet removed can be used as the reception signal in the second stage.

[0182] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0183] FIG. 18 illustrates an example of a signal processing procedure in a second stage according to embodiments of the present disclosure.

[0184] Referring to FIG. 18, a block diagram is provided illustrating a signal processing procedure of the second stage, including a method for determining whether a receiving device performs NC and selecting SIC / SNIC. While the following example describes a signal processing procedure in an MU-MIMO environment (e.g., FIG. 12 described above), it can also be applied to SU-MIMO (e.g., FIG. 13 described above).

[0185] At step 1810, the receiving device can perform channel estimation for the received signal (Y_(1)). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0186] In step 1820, the receiving device can perform channel equalization through an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion for the received signal (Y_(1)). Specifically, channel equalization can be a procedure for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range. In addition, the receiving device can decode the nonlinearity information experienced by the received signal from the received signal to be decoded in the second stage. ) can be obtained. Nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure. The receiving device can determine whether to perform NC by comparing the nonlinearity of the second packet (e.g., the signal received through the second layer) and the EVM threshold value. At this time, since the nonlinearity (-28 dB) of the second packet (e.g., the signal received through the second layer) is less than the EVM threshold value (-27 dB), the receiving device can identify that NC is not performed.

[0187] At step 1830, if the receiving device identifies that it does not perform NC, the receiving device may perform demodulation on the second packet. Accordingly, the demodulated signal for the second packet (e.g., ) can be printed.

[0188] At step 1840, the receiving device receives the demodulated signal for the second packet (e.g., ) can perform IDFT on the decrypted data packet (e.g., ) when restoring the original signal, nonlinearity information ( ) can be considered. At this time, since the nonlinearity (-28 dB) of the second packet is smaller than the EVM threshold (-25 dB) of the third packet (e.g., the signal received through the third layer), the receiving device can be identified as performing SIC by considering the complexity of the signal processing procedure rather than the nonlinearity.

[0189] At step 1850, if the receiving device identifies that it is performing SIC, the receiving device will receive nonlinearity information ( ) can be used to restore the second packet without considering the second packet. And the receiving device can remove the restored second packet from the reception signal (Y_(1)), and the output signal (Y_(2)) with the component for the second packet removed can be used as the reception signal in the third stage.

[0190] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0191] FIG. 19 illustrates an example of a signal processing procedure in a third stage according to embodiments of the present disclosure.

[0192] Referring to FIG. 19, a block diagram is provided illustrating a signal processing procedure of the third stage, including a method for determining whether a receiving device performs NC and selecting SIC / SNIC. While the following example describes a signal processing procedure in an MU-MIMO environment (e.g., FIG. 12 described above), it can also be applied to SU-MIMO (e.g., FIG. 13 described above).

[0193] At step 1910, the receiving device can perform channel estimation on the received signal (Y_(2)). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0194] In step 1920, the receiving device can perform channel equalization through an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion for the received signal (Y_(2)). Specifically, channel equalization can be a procedure for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range. In addition, the receiving device can decode the nonlinearity information experienced by the received signal from the received signal to be decoded in the third stage ( ) can be obtained. Nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure. The receiving device can determine whether to perform NC by comparing the nonlinearity of the third packet (e.g., the signal received through the third layer) with the EVM threshold value. At this time, since the nonlinearity (-24 dB) of the third packet (e.g., the signal received through the third layer) is greater than the EVM threshold value (-25 dB), the receiving device can identify that NC is performed by considering the nonlinearity.

[0195] At step 1930, if the receiving device identifies that it performs NC, the receiving device may perform IDFT for the third packet.

[0196] At step 1940, the receiving device can perform the NC after performing the IDFT. Specifically, the receiving device can perform the nonlinearity information ( ) can be used to perform NC on the third packet.

[0197] At step 1950, the receiving device can perform DFT after performing NC.

[0198] At step 1960, the receiving device can perform demodulation on the third packet that performed NC. Thus, the demodulated signal for the third packet (e.g., ) can be printed.

[0199] At step 1970, the receiving device receives the demodulated signal for the third packet (e.g., ) can perform IDFT on the decrypted data packet (e.g., ) when restoring the original signal, nonlinearity information ( ) can be considered. At this time, since the nonlinearity (-24 dB) of the third packet is greater than the EVM threshold (-32 dB) of the second packet (e.g., the signal received through the second layer), the receiving device can be identified as performing SNIC by considering the nonlinearity rather than the complexity of the signal processing procedure.

[0200] At step 1980, if the receiving device identifies itself as performing SNIC, the receiving device will receive nonlinearity information ( ) can be taken into account to restore the third packet. Then, the receiving device can remove the restored third packet from the reception signal (Y_(2)), and the output signal (Y_(3)) with the component for the third packet removed can be used as the reception signal in the second stage.

[0201] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0202] FIG. 20 illustrates an example of a signal processing procedure in the fourth stage according to embodiments of the present disclosure.

[0203] Referring to FIG. 20, a block diagram is provided illustrating a signal processing procedure of the fourth stage, including a method for determining whether a receiving device performs NC and selecting SIC / SNIC. While the following example describes a signal processing procedure in an MU-MIMO environment (e.g., FIG. 12 described above), it can also be applied to SU-MIMO (e.g., FIG. 13 described above).

[0204] At step 2010, the receiving device can perform channel estimation for the received signal (Y_(3)). For example, the receiving device can estimate the channel state between the transmitting device and the receiving device based on a reference signal that is commonly known to the transmitting device. At this time, the estimated channel is can be expressed as

[0205] In step 2020, the receiving device can perform channel equalization through an equalizer based on the estimated channel information. For example, the receiving device can compensate for channel distortion for the received signal (Y_(3)). Specifically, channel equalization can be a procedure for the receiving device to have uniform amplitude and phase characteristics across the entire frequency range. In addition, the receiving device can decode the nonlinearity information experienced by the received signal from the received signal to be decoded in the fourth stage ( ) can be obtained. Nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. However, the receiving device may perform the nonlinearity information acquisition procedure before the channel equalization procedure. The receiving device can determine whether to perform NC by comparing the nonlinearity of the fourth packet (e.g., the signal received through the fourth layer) and the EVM threshold value. At this time, since the nonlinearity (-31 dB) of the fourth packet (e.g., the signal received through the fourth layer) is greater than the EVM threshold value (-32 dB), the receiving device can identify that NC is performed by considering the nonlinearity.

[0206] At step 2030, if the receiving device identifies that it performs NC, the receiving device may perform IDFT for the fourth packet.

[0207] At step 2040, the receiving device can perform NC after performing IDFT. Specifically, the receiving device can perform NC using nonlinearity information (obtained before step 2030) ) can be used to perform NC for the fourth packet.

[0208] At step 2050, the receiving device can perform DFT after performing NC.

[0209] At step 2060, the receiving device can perform demodulation on the fourth packet that performed NC. Therefore, the demodulated signal for the fourth packet (e.g., ) can be printed.

[0210] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0211] FIG. 21 illustrates the operation sequence of a receiving device according to embodiments of the present disclosure.

[0212] Referring to FIG. 21, an operation sequence for determining whether to perform NC based on nonlinearity information and selecting SIC or SNIC in order for a receiving device to perform continuous interference cancellation on a received signal (hereinafter, a plurality of data packets) can be described. Hereinafter, the receiving device can perform the operations of FIGS. 8 to 20 described above, and redundant descriptions can be omitted.

[0213] At step 2110, the receiving device can receive a plurality of superimposed signals (e.g., a plurality of data packets) from at least one transmitting device. For example, the receiving device can receive a plurality of superimposed data packets from a single transmitting device, or can receive superimposed data packets from each of the plurality of transmitting devices.

[0214] At step 2120, the receiving device can decrypt a first packet (hereinafter, referred to as the first data packet) among the plurality of data packets. At this time, the decryption of the first data packet can be performed based on information regarding nonlinearity between at least one transmitting device and a receiving device. For example, the nonlinearity information can be obtained by utilizing a reference signal commonly known to the transmitting device and the receiving device, such as an existing reference signal (e.g., including at least one of DMRS, PSS, SSS, SRS, or CSI-RS) or a reference signal separately defined for NC. The receiving device can determine whether to perform NC by comparing the nonlinearity of the first data packet with an EVM threshold value.

[0215] At step 2130, the receiving device can restore the decrypted first data packet based on information regarding the reception signal quality of each of the second packet (hereinafter, referred to as the second data packet) among the plurality of data packets and the decrypted first data packet. For example, if the nonlinearity of the first data packet is greater than the EVM threshold of the first data packet, the receiving device can identify that it will perform SNIC considering the nonlinearity rather than the complexity of the signal processing procedure.

[0216] At step 2140, the receiving device can remove the restored first data packet from the plurality of data packets.

[0217] However, the above-described operations are merely examples and are not limited to the embodiments of the present disclosure. Accordingly, some of the above-described operations may be combined or separated into two or more operations. Furthermore, at least one of the above-described operations may be deleted, or a new operation may be added. In this case, at least one of the added operations may be organically combined with the above-described operations.

[0218] FIG. 22 illustrates the BER performance of a receiver when NC is applied according to embodiments of the present disclosure.

[0219] Referring to FIG. 22, a graph is shown showing the BER performance according to the type of receiver under specific conditions (e.g., TDL-C channel, 4Rx, 3UEs, 1024-DFT, 300REs, 256QAM, when a PA with 3.5% EVM is applied) when nonlinearity is present. FIG. 22 can show the reception performance when performing SIC, OSIC, and ZF in a situation where distorted signals due to nonlinear characteristics are received by sharing frequency, time, and space. For example, in FIG. 22, the cases where there is no nonlinear characteristic, when a PA with 3.5% EVM is applied, and when AI-NC according to an embodiment of the present disclosure is applied can be compared in each of the receiving devices performing the OSIC, SIC, and ZF methods. In each of the receiving devices performing the OSIC, SIC, and ZF methods, the case where AI-NC according to an embodiment of the present disclosure is applied can have a higher BER at the same SNR compared to the case where there is no nonlinear characteristic. However, in each of the receiving devices performing the OSIC, SIC, and ZF methods, the case where the AI-NC according to the embodiment of the present disclosure is applied may have a lower BER at the same SNR compared to the case where nonlinear characteristics are generated by applying the PA. Therefore, as long as nonlinear characteristics are generated by applying the PA, the AI-NC method according to the embodiment of the present disclosure can be applied to alleviate the degradation of reception performance due to nonlinearity.

[0220] Therefore, according to an embodiment of the present disclosure, unlike a general SIC receiving technology, by applying decoding that takes nonlinearity into account and restoration of the original signal using the decoded signal, even in a situation where signals distorted due to nonlinearity are received by sharing frequency, time, and space, error propagation problems can be alleviated, thereby achieving excellent receiving performance.

[0221] According to various embodiments of the present disclosure, a method performed by a receiving device in a wireless communication system includes the steps of receiving a plurality of data packets from at least one transmitting device, decoding a first data packet among the plurality of data packets, reconstructing the decoded first data packet based on a reception signal quality of a second data packet among the plurality of data packets and a reception signal quality of the decoded first data packet, and canceling the reconstructed first data packet from the plurality of data packets, wherein the decoding may be performed based on information about a nonlinearity between the at least one transmitting device and the receiving device.

[0222] In one embodiment, the step of performing the decryption includes the step of comparing a threshold value regarding the received signal quality of the decrypted first data packet with a received signal quality based on the information regarding the nonlinearity, and the step of compensating for the nonlinearity for the first data packet when the received signal quality based on the information regarding the nonlinearity is greater than the threshold value, wherein the threshold value may be based on a modulation and coding scheme (MCS) of the first data packet.

[0223] In one embodiment, the step of restoring the decrypted first data packet includes the step of identifying a restoration method of the decrypted first data packet based on a threshold value regarding the reception signal quality of the second data packet and a reception signal quality based on information regarding the nonlinearity of the first data packet, wherein the threshold value is based on an MCS of the second data packet, and the restoration method includes successive interference cancellation (SIC) or successive nonlinear interference cancellation (SNIC), wherein the SIC may be a sequential interference cancellation method that does not consider information regarding the nonlinearity, and the SNIC may be a sequential interference cancellation method based on information regarding the nonlinearity.

[0224] In one embodiment, if the received signal quality based on the information about the nonlinearity is less than or equal to the threshold value, the decrypted first data packet may be restored by SIC.

[0225] In one embodiment, if the received signal quality based on the information about the nonlinearity is greater than the threshold value, the decrypted first data packet may be restored by the SNIC.

[0226] In one embodiment, the method further comprises a step of obtaining information about the nonlinearity based on a reference signal received from the at least one transmitting device, wherein the reference signal may include at least one of a demodulation reference signal (DMRS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a sounding reference signal (SRS), or a channel state information reference signal (CSI-RS).

[0227] In one embodiment, the information about the received signal quality may include at least one of error vector magnitude (EVM), modulation error (MER), mean square error (MSE), or signal-to-noise ratio (SNR).

[0228] In one embodiment, each of said at least one transmitting device comprises a terminal,

[0229] When the plurality of data packets are received from a plurality of terminals, the first data packet is a data packet received from the first terminal, the second data packet is a data packet received from the second terminal, and each of the first terminal and the second terminal may be indexed based on the strength of the received signal.

[0230] In one embodiment, each of said at least one transmitting device comprises a terminal,

[0231] When the plurality of data packets are received from one terminal, each of the first data packet and the second data packet may be received through a plurality of antennas associated with the receiving device, and each of the first data packet and the second data packet may be indexed based on the strength of the received signal.

[0232] In one embodiment, the decoding may be performed based on a discrete Fourier transform (DFT) of channel estimation information with the at least one transmitting device and information about the nonlinearity.

[0233] According to various embodiments of the present disclosure, a receiving device of a wireless communication system comprises a transceiver, and at least one control unit connected to the transceiver, wherein the at least one control unit is configured to: receive a plurality of data packets from at least one transmitting device, decode a first data packet among the plurality of data packets, reconstruct the decoded first data packet based on a reception signal quality of a second data packet among the plurality of data packets and a reception signal quality of the decoded first data packet, and cancel the reconstructed first data packet from the plurality of data packets, wherein the decoding may be performed based on information about nonlinearity between the at least one transmitting device and the receiving device.

[0234] In one embodiment, at least one control unit is configured to compare a threshold value regarding the received signal quality of the decrypted first data packet with a received signal quality based on the information regarding the nonlinearity, and to compensate for the nonlinearity for the first data packet if the received signal quality based on the information regarding the nonlinearity is greater than the threshold value, wherein the threshold value may be based on a modulation and coding scheme (MCS) of the first data packet.

[0235] In one embodiment, the at least one control unit is configured to identify a restoration method of the decrypted first data packet based on a threshold value regarding the reception signal quality of the second data packet and a reception signal quality based on information regarding the nonlinearity of the first data packet, wherein the threshold value is based on an MCS of the second data packet, and the restoration method includes successive interference cancellation (SIC) or successive nonlinear interference cancellation (SNIC), wherein the SIC may be a sequential interference cancellation method that does not consider information regarding the nonlinearity, and the SNIC may be a sequential interference cancellation method based on information regarding the nonlinearity.

[0236] In one embodiment, if the received signal quality based on the information about the nonlinearity is less than or equal to the threshold value, the decrypted first data packet may be restored by SIC.

[0237] In one embodiment, if the received signal quality based on the information about the nonlinearity is greater than the threshold value, the decrypted first data packet may be restored by the SNIC.

[0238] In one embodiment, the at least one control unit is further configured to obtain information about the nonlinearity based on a reference signal received from the at least one transmitting device, wherein the reference signal may include at least one of a demodulation reference signal (DMRS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a sounding reference signal (SRS), or a channel state information reference signal (CSI-RS).

[0239] In one embodiment, the information about the received signal quality may include at least one of error vector magnitude (EVM), modulation error (MER), mean square error (MSE), or signal-to-noise ratio (SNR).

[0240] In one embodiment, each of the at least one transmitting device includes a terminal, and when the plurality of data packets are received from a plurality of terminals, the first data packet is a data packet received from the first terminal, the second data packet is a data packet received from the second terminal, and each of the first terminal and the second terminal may be indexed based on the strength of a received signal.

[0241] In one embodiment, each of said at least one transmitting device comprises a terminal,

[0242] When the plurality of data packets are received from one terminal, each of the first data packet and the second data packet may be received through a plurality of antennas associated with the receiving device, and each of the first data packet and the second data packet may be indexed based on the strength of the received signal.

[0243] In one embodiment, the decoding may be performed based on a discrete Fourier transform (DFT) of channel estimation information with the at least one transmitting device and information about the nonlinearity.

[0244] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0245] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0246] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0247] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0248] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0249] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. A method performed by a receiving device in a wireless communication system, A step of receiving a plurality of data packets from at least one transmitting device; A step of decoding a first data packet among the plurality of data packets; A step of reconstructing the decrypted first data packet based on the reception signal quality of the second data packet among the plurality of data packets and the reception signal quality of the decrypted first data packet; and A step of canceling the restored first data packet from the plurality of data packets, A method wherein said decryption is performed based on information about nonlinearity between said at least one transmitting device and said receiving device.

2. In the first paragraph, the step of performing the decryption is as follows: A step of comparing the received signal quality of the decrypted first data packet with a threshold value regarding the received signal quality based on the information regarding the nonlinearity; and A step of compensating for nonlinearity for the first data packet, if the received signal quality based on the information about the nonlinearity is greater than the threshold value, A method wherein the above threshold value is based on a modulation and coding scheme (MCS) of the first data packet.

3. In the first paragraph, the step of restoring the decrypted first data packet is: A step of identifying a restoration method of the decrypted first data packet based on a received signal quality based on a threshold value regarding the received signal quality of the second data packet and information regarding the nonlinearity of the first data packet, The above threshold is based on the MCS of the second data packet, The above restoration method includes successive interference cancellation (SIC) or successive nonlinear interference cancellation (SNIC). The above SIC is a sequential interference cancellation method that does not consider information about the nonlinearity. The above SNIC is a method of sequential interference cancellation based on information about the nonlinearity.

4. In paragraph 3, A method wherein the decoded first data packet is restored by SIC if the received signal quality based on the information about the nonlinearity is less than or equal to the threshold value.

5. In paragraph 3, A method wherein the decrypted first data packet is restored by the SNIC if the received signal quality based on the information about the nonlinearity is greater than the threshold value.

6. In paragraph 1, the method, Further comprising a step of obtaining information about the nonlinearity based on a reference signal received from at least one transmitting device, A method wherein the above reference signal includes at least one of a demodulation reference signal (DMRS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a sounding reference signal (SRS), or a channel state information reference signal (CSI-RS).

7. In paragraph 1, A method wherein the information about the quality of the received signal includes at least one of error vector magnitude (EVM), modulation error (MER), mean square error (MSE), or signal-to-noise ratio (SNR).

8. In paragraph 1, Each of said at least one transmitting device comprises a terminal, When the above multiple data packets are received from multiple terminals, the first data packet is a data packet received from the first terminal, and the second data packet is a data packet received from the second terminal. A method wherein each of the first terminal and the second terminal is indexed based on the strength of the received signal.

9. In a receiving device of a wireless communication system, Transmitter and receiver; and At least one control unit connected to the above transceiver unit, At least one of the above control units: receiving a plurality of data packets from at least one transmitting device; Decoding a first data packet among the above multiple data packets, Reconstructing the decrypted first data packet based on the reception signal quality of the second data packet among the plurality of data packets and the reception signal quality of the decrypted first data packet, and The restored first data packet is set to be cancelled from the plurality of data packets, A receiving device, wherein the decryption is performed based on information about nonlinearity between the at least one transmitting device and the receiving device.

10. In paragraph 9, at least one control unit, Comparing the received signal quality based on the threshold value regarding the received signal quality of the decrypted first data packet and the information regarding the nonlinearity, and If the received signal quality based on the information about the nonlinearity is greater than the threshold value, the nonlinearity for the first data packet is set to be compensated, A receiving device wherein the above threshold value is based on a modulation and coding scheme (MCS) of the first data packet.

11. In paragraph 9, at least one control unit, It is set to identify a restoration method of the decrypted first data packet based on the reception signal quality based on the threshold value regarding the reception signal quality of the second data packet and the information regarding the nonlinearity of the first data packet, The above threshold is based on the MCS of the second data packet, The above restoration method includes successive interference cancellation (SIC) or successive nonlinear interference cancellation (SNIC). The above SIC is a sequential interference cancellation method that does not consider information about the nonlinearity. A receiving device wherein the above SNIC is a sequential interference cancellation method based on information about the above nonlinearity.

12. In paragraph 11, A receiving device, wherein the decoded first data packet is restored by SIC if the received signal quality based on the information about the nonlinearity is less than or equal to the threshold value.

13. In paragraph 11, A receiving device, wherein the decrypted first data packet is restored by the SNIC when the received signal quality based on the information about the nonlinearity is greater than the threshold value.

14. In paragraph 9, at least one control unit, Further configured to obtain information about the nonlinearity based on a reference signal received from at least one transmitting device, A receiving device, wherein the reference signal includes at least one of a demodulation reference signal (DMRS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a sounding reference signal (SRS), or a channel state information reference signal (CSI-RS).

15. In paragraph 9, A receiving device, wherein the information about the quality of the received signal includes at least one of EVM (error vector magnitude), MER (modulation error), MSE (mean square error), or SNR (signal-to-noise ratio).

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