Low complexity widely linear reception processing in multi-antenna wireless communication system and method thereof

Abstract

The present invention relates to a communication technique and a system for integrating 5G and subsequent communication systems with IoT technology to support a higher data transmission rate than that of a 4G system. The present invention can be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G and subsequent communication technologies and IoT-related technologies. A receiving device according to the present invention receives OFDM signals through a plurality of antennas, aligns the received signals, converts at least one received signal symbol among the aligned received signals into a designated symbol, estimates the data symbol of the received signals based on designated conditions, and determines the data symbol of the received signals by synthesizing at least one of the converted received signals among the estimated received signals.

Description

Technology Field

[0001] The present invention relates to a low-complexity optical linear receiver for a wireless communication system, and more specifically, to providing a receiver having very low complexity to improve the processing efficiency of a received signal. Background Technology

[0002] Efforts are being made to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems. For this reason, 5G or pre-5G communication systems are referred to as systems beyond the 4G network or systems following the LTE system. To achieve high data transmission rates, the implementation of 5G communication systems in the mmWave band (e.g., the 60 GHz band) is being considered. To mitigate path loss and increase transmission distance in the mmWave band, technologies such as beamforming, massive MIMO, full Dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antennas are being discussed for 5G communication systems. In addition, to improve the network of the system, the development of technologies such as advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation is taking place in 5G communication systems.In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (nonorthogonal multiple access), and SCMA (sparse code multiple access) are being developed in 5G systems.

[0003] Meanwhile, the Internet is evolving from a human-centric network where humans generate and consume information into an IoT (Internet of Things) network that processes information by exchanging it among distributed components, such as objects. IoE (Internet of Everything) technology, which combines IoT with Big Data processing technologies through connections with cloud servers, is also emerging. To implement IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required; consequently, technologies such as sensor networks, Machine-to-Machine (M2M) communication, and Machine-Type Communication (MTC) are currently being researched to facilitate the connection of objects. In an IoT environment, intelligent IT services that create new value for human life by collecting and analyzing data generated from connected objects can be provided. Through the convergence and integration of existing IT technologies with various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0004] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, Machine to Machine (M2M), and Machine Type Communication (MTC) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of cloud RAN as a big data processing technology, as previously described, can also be considered an example of the convergence of 5G and IoT technologies.

[0005] In 5G mobile communication, efforts are being made to improve the communication performance of cell-edge users to support faster transmission speeds while having wider cell coverage than 4G mobile communication. In particular, there is an attempt to increase communication sensitivity by significantly amplifying the power of cell-edge users; however, due to the non-linearity of power amplifiers and battery capacity issues, the PAPR performance of the waveform used at the physical layer is very important.

[0006] 5G mobile communication incorporates DFT-spread OFDM technology using ð / 2-BPSK symbols in the uplink to reduce PAPR. However, since ð / 2-BPSK symbols are improper symbols, reception performance is degraded when using linear receivers designed for conventional QPSK and QAM symbols. On the other hand, while using a widely linear optical receiver can improve reception performance, it has the disadvantage of very high computational complexity. Furthermore, processing signals received by multiple antennas with a widely linear optical receiver requires significantly higher complexity compared to a single antenna. The problem to be solved

[0007] When using π / 2-BPSK symbols with low PAPR characteristics, sufficient performance can be obtained by using an optical linear receiver due to the imperfect nature of BPSK. In particular, in 5G mobile communication, when using ð / 2-BPSK symbols with low PAPR characteristics, sufficient performance can be obtained by using an optical linear receiver due to the imperfect nature of BPSK. In particular, in 5G mobile communication, multiple layers can be assigned to the same RB, and as a result, multiple symbols including ð / 2-BPSK symbols can be mixed and received simultaneously in the same frequency band through multiple antennas.

[0008] In other words, while it is possible to induce a linear optical receiver when one or more imperfect signals are input, it generally has the disadvantage of high computational complexity. Furthermore, as the number of multiple antennas increases, the computational complexity required to process the received signals simultaneously becomes so high that it is difficult to implement in practice.

[0009] According to various embodiments of the present invention, a receiver applicable to a signal containing at least one ð / 2 phase-shifted non-proper symbol (e.g., ð / 2-BPSK, ð / 2-PAM) in a receiver using multiple antennas can provide a receiver capable of drastically reducing computational complexity under specific conditions. means of solving the problem

[0010] According to one embodiment of the present invention, a receiving device method of a wireless communication system comprises: receiving orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; aligning received signal symbols included in the received signals; converting at least one quadrature phase shift keying (QPSK) symbol or quadrature amplitude modulation (QAM) symbol among the aligned received signal symbols into π / 2 phase-shifted pulse amplitude modulation (PAM) symbols; estimating data symbols of the aligned received signal symbols including the at least one converted received signal symbol; synthesizing at least a portion of the π / 2 phase-shifted PAM symbols among the estimated data symbols to convert them into the QPSK symbol or the QAM symbol; and determining the estimated data symbols including the converted QPSK symbol or the QAM symbol as the data symbols of the received signals.

[0011] Here, the step of aligning the received signal symbols included in the above-mentioned continuously received signals can align the received signal symbols as a vector.

[0012] Here, the step of converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols may further include the step of newly aligning the received signal symbols based on the converted π / 2 phase-shifted PAM symbols.

[0013] Here, the step of estimating data symbols of the aligned received signal symbols including at least one converted received signal symbol can estimate the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols.

[0014] Here, the step of estimating data symbols of the aligned received signal symbols including at least one converted received signal symbol may apply the inverse of a matrix in which at least one matrix block includes a block diagonal matrix to the channel matrix of the received signal symbols based on a specified condition.

[0015] Here, the specified condition is that at least one symbol among the received signals is in the following mathematical formula,

[0016]

[0017] (Here, f Is f The phase transition value M satisfying ∈[0 ð] is The number of allocated subcarriers satisfying, is an arbitrary natural number, k is an integer)

[0018] In the above case, M may satisfy the condition of being a multiple of 4.

[0019] Here, the step of converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols may include the step of substituting at least one QPSK symbol or QAM symbol among the aligned received signal symbols so that a constellation rotation matrix is ​​extracted, and determining at least a portion of each of the real part and the imaginary part of the substituted QPSK symbol or QAM symbol as the π / 2 phase-shifted PAM symbols.

[0020] Here, the step of converting the π / 2 phase-shifted PAM symbol among the estimated data symbols into the QPSK symbol or the QAM symbol may include: the step of determining the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion among the π / 2 phase-shifted PAM symbols of the estimated data symbols; and the step of combining the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion.

[0021] Here, the step of determining the real and imaginary parts of the QPSK symbol or QAM symbol before transformation among the π / 2 phase-shifted PAM symbols of the estimated data symbols may further include the step of applying the constellation rotation matrix to each of the real and imaginary parts of the QPSK symbol or QAM symbol before transformation.

[0022] Here, the specified condition is that the received signals may include at least one ð / 2-BPSK symbol.

[0023] According to various embodiments of the present invention, a receiving device of a wireless communication system comprises: at least one receiver that receives orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; and at least one processing unit functionally coupled with the at least one receiver. and a storage unit for storing the processing results of the processing unit; wherein the at least one processing unit aligns the received signal symbols included in the received signals received at any time, converts at least one quadrature phase shift keying (QPSK) symbol or quadrature amplitude modulation (QAM) symbol among the aligned received signal symbols into π / 2 phase shift pulse amplitude modulation (PAM) symbols, estimates the data symbols of the aligned received signal symbols including the at least one converted received signal symbol, synthesizes at least some of the π / 2 phase shift PAM symbols among the estimated data symbols to convert them into the QPSK symbol or the QAM symbol, and processes the estimated data symbols including the converted QPSK symbol or the QAM symbol to determine the data symbols of the received signals.

[0024] Here, the at least one processing unit can arrange the received signal symbols as a vector.

[0025] Here, the at least one processing unit can, in converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols, newly align the received signal symbols based on the converted π / 2 phase-shifted PAM symbols.

[0026] Here, the at least one processing unit can estimate the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols.

[0027] Here, the at least one processing unit, in estimating the data symbols of the aligned received signal symbols including the converted at least one received signal symbol, may apply the inverse of a matrix in which at least one matrix block includes a block diagonal matrix to the channel matrix of the received signal symbols based on a specified condition.

[0028] Here, the specified condition is that at least one symbol among the received signals is in the following mathematical formula,

[0029]

[0030] (Here, f Is f The phase transition value M satisfying ∈[0 ð] is The number of allocated subcarriers satisfying, is an arbitrary natural number, k is an integer)

[0031] In the above case, M may satisfy the condition of being a multiple of 4.

[0032] Here, the at least one processing unit, in converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols, may substitute at least one QPSK symbol or QAM symbol among the aligned received signal symbols so that a constellation rotation matrix is ​​extracted, and determine at least a portion of each of the real part and the imaginary part of the substituted QPSK symbol or QAM symbol as the π / 2 phase-shifted PAM symbols.

[0033] Here, the at least one processing unit, in converting the π / 2 phase-shifted PAM symbol among the estimated data symbols into the QPSK symbol or the QAM symbol, determines the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion among the π / 2 phase-shifted PAM symbols of the estimated data symbols, and can combine the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion.

[0034] Here, the at least one processing unit may apply the constellation rotation matrix to each of the real and imaginary parts of the QPSK symbol or QAM symbol before transformation among the π / 2 phase-shifted PAM symbols of the estimated data symbols when determining the real and imaginary parts of the QPSK symbol or QAM symbol before transformation.

[0035] Here, the specified condition is that the received signals may include at least one ð / 2-BPSK symbol. Effects of the invention

[0036] According to various embodiments of the present invention, when specific parameter conditions are satisfied, a linear optical receiver can be implemented very simply when the signal received by multiple antennas is a DFT-spread OFDM signal using at least one ð / 2-BPSK symbol or ð / 2-PAM symbol.

[0037] In the present invention, when specific parameter conditions are satisfied, the complexity of implementing a linear optical receiver for existing multiple antennas can be drastically reduced by reflecting the characteristics of a signal including an improper symbol and the linear phase shift characteristics. Brief explanation of the drawing

[0038] FIG. 1 illustrates a wireless communication environment according to one embodiment of the present invention. FIG. 2 illustrates the configuration of an electronic device in a wireless communication system according to various embodiments of the present disclosure. FIG. 3 illustrates a communication unit configuration including a transmitter of an electronic device in a wireless communication system according to one embodiment of the present invention. FIG. 4 illustrates a communication unit configuration including a receiver of an electronic device in a wireless communication system according to one embodiment of the present invention. FIG. 5 illustrates the operation of receiving a signal transmitted from a transmitting device in a receiving device according to one embodiment of the present invention. FIG. 6 illustrates the operation of aligning signals in a receiving device according to one embodiment of the present invention. FIG. 7 illustrates the operation of converting the symbol of a signal in a receiving device according to one embodiment of the present invention. FIG. 8 illustrates the operation of estimating a symbol vector in a receiving device according to one embodiment of the present invention. FIG. 9 illustrates the operation of converting the symbol of an estimated signal in a receiving device according to one embodiment of the present invention. FIG. 10 is a diagram comparing the processing of a conventional linear optical receiver and a low-complexity linear optical receiver proposed in the present invention in a receiving device according to one embodiment of the present invention. FIG. 11 illustrates the main configuration of a receiver of a receiving device according to one embodiment of the present invention. FIG. 12 illustrates the flow of an operation for estimating the symbol of a received signal in a receiving device according to one embodiment of the present invention. Specific details for implementing the invention

[0039] In describing the embodiments of the present invention, technical details that are well known in the technical field to which the present invention belongs and are not directly related to the present invention have been omitted. This is intended to convey the essence of the present invention more clearly without obscuring it by omitting unnecessary explanations.

[0040] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0041] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments described below but can be implemented in various different forms. These embodiments are provided merely to ensure that the invention is complete and to fully inform those skilled in the art of the scope of the invention, and the invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0042] At this time, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing the means of instruction to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0043] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For instance, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to their corresponding functions.

[0044] In this embodiment, the term "part" refers to a software or hardware component, such as an FPGA or ASIC, and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to operate one or more processors. Accordingly, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." Furthermore, the components and "parts" may be implemented to operate one or more CPUs within a device or secure multimedia card. In addition, in the embodiment, '~part' may include one or more processors.

[0045] For the convenience of the following description, the present invention uses terms and names defined in the standards for 5G, NR (New Radio), and LTE (Long Term Evolution) systems. However, the present invention is not limited by these terms and names and can be applied in the same way to systems conforming to other standards. For example, it is obvious that it can be applied to 6G or pre-6G communication systems, which are communication systems after 5G.

[0046] Terms referring to signals, terms referring to device components, etc., used in the following description are examples provided for the convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0047] In addition, various embodiments are described using terms used in some communication standards (e.g., 3rd Generation Partnership Project, 3GPP), but these are merely illustrative examples and can be easily modified and applied to other communication systems for the same or similar operations.

[0048] The present invention relates to a method and apparatus for processing a signal received in a wireless communication system. Specifically, the present invention can improve signal processing efficiency by receiving a wireless signal through a plurality of antennas and processing the received wireless signal using a receiver with significantly low computational complexity.

[0049] As an example of this, the receiver may include an optical linear minimum mean squared-error (MMSE) estimator for low complexity implementation, which will be described in detail with reference to the drawings.

[0050] FIG. 1 illustrates a wireless communication environment according to one embodiment of the present invention.

[0051] Referring to FIG. 1, a transmitting device (110) and a receiving device (120) are shown as part of a node using a wireless channel in a wireless communication environment (100). According to one embodiment, the transmitting device (110) or the receiving device (120) may be a device configured to process an orthogonal frequency division multiplexing (OFDM) signal.

[0052] The transmitting device (110) may be configured to include at least one antenna and a transmitter. In this case, the transmitting device (110) may transmit a wireless signal to the receiving device (120) through a wireless channel.

[0053] The receiving device (120) may be configured to include a plurality of antennas and receivers. However, the receiving device (120) may be a device that includes not only a receiver but also a transmitter, and may operate as a transmitting device that transmits signals. In other words, the receiving device (120) may transmit control information (e.g., channel information) to the transmitting device as needed, as well as transmit data.

[0054] Likewise, the transmitting device (110) may be configured to include a receiver and may receive a wireless signal from at least one other transmitting device. It is obvious that if the transmitting device (110) is configured to include a receiver and a plurality of antennas, it may operate as the receiving device (120) of the present invention.

[0055] As described above, the transmitting device (110) configured to include a transmitter and the receiving device (120) configured to include a receiver may each be configured to further include a receiver and a transmitter. Additionally, the transmitter or receiver is a configuration named according to its function and may be expressed as a communication unit.

[0056] In various embodiments of the present invention, the transmitting device (110) or the receiving device (120) is named only according to the function of the role primarily performed, and both may be referred to as electronic devices. According to various embodiments of the present invention, the electronic device may be configured to include a terminal, 'user equipment (UE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal', 'user device', 'base station', 'access point (AP)', 'eNodeB (eNB)', '5th generation node', 'wireless point', and 'transmission / reception point (TRP)', or may include at least one of other terms having an equivalent technical meaning, or may be configured as at least one of them. The electronic device may consist of devices included in the category of wireless communication devices.

[0057] According to one embodiment, during downlink communication, the transmitting device (110) may be a base station and the receiving device (120) may be a terminal. As another example, during uplink communication, the transmitting device (110) may be a terminal and the receiving device (120) may be a base station. Additionally, during device-to-device (D2D) communication, the transmitting device (110) may be a terminal and the receiving device (120) may be another terminal. Here, D2D communication may be referred to as sidelink communication. Additionally, the transmitting device (110) may be a base station and the receiving device (120) may be another base station. In some embodiments, the transmitting device (110) and the receiving device (120) may perform signaling through a backhaul. The backhaul may be a wireless backhaul. In addition to the examples listed, the transmitting device (110) and the receiving device (120) may be various devices capable of transmitting and receiving signals.

[0058] A base station is network infrastructure that provides wireless access to terminals. In addition to base stations, base stations include 'access points (APs)', 'eNodeBs (eNBs)', and '5G nodes (5 th It may be referred to as 'generation node', '5G NodeB (NB)', 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning.

[0059] A terminal is a device used by a user that communicates with a base station via a wireless channel. In some cases, the terminal may be operated without user involvement. That is, the terminal is a device that performs machine-type communication (MTC) and may or may not be carried by the user. The terminal may be referred to by terms other than "terminal," such as "user equipment (UE)," "mobile station," "subscriber station," "remote terminal," "wireless terminal," or "user device," or other terms having an equivalent technical meaning.

[0060] FIG. 2 illustrates the configuration of an electronic device in a wireless communication system according to various embodiments of the present disclosure.

[0061] According to one embodiment, the configuration of the electronic device (200) illustrated in FIG. 2 can be understood as the configuration of a receiving device (120). Referring to FIG. 2, the receiving device (120) may include a communication unit (210), a processing unit (220), and a storage unit (230).

[0062] The communication unit (210) can perform operations to receive a signal through a wireless channel. When receiving a signal, the communication unit (210) can down-convert the RF band signal received through the antenna into a baseband signal, and can restore the received bit sequence through demodulation and decoding of the baseband signal. To this end, according to one embodiment, the communication unit (210) may include a decoder, a demodulator, an analog-to-digital converter (ADC), a receiving filter, an amplifier, a mixer, and an oscillator.

[0063] In addition, if the communication unit (210) includes a transmission function as described above, the communication unit (210) can perform a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting control information, the communication unit (210) can generate modulation symbols by encoding and modulating the transmission bit sequence. In addition, the communication unit (210) can up-convert the baseband signal into an RF (radio frequency) band signal and then transmit it through an antenna. To this end, according to one embodiment, the communication unit (210) may include an encoder, a modulator, a DAC (digital to analog converter), and a transmission filter.

[0064] The communication unit (210) includes a plurality of antennas and can receive a plurality of streams through each of the plurality of antennas. In addition, the communication unit (210) may include a plurality of RF chains and can perform beamforming.

[0065] For beamforming, the communication unit (210) can adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements, i.e., perform analog beamforming, or perform beamforming for digital signals, i.e., digital beamforming.

[0066] Additionally, the communication unit (210) may include different communication modules to process signals of different frequency bands. Furthermore, the communication unit (210) may include multiple communication modules to support multiple different wireless access technologies. For example, different wireless access technologies may include Bluetooth Low Energy (BLE), Wi-Fi (Wireless Fidelity), WiGig (WiFi Gigabyte), and cellular networks (e.g., LTE, LTE-A, 5G (5th generation) networks). Additionally, different frequency bands may include super high frequency (SHF) bands (e.g., 2.5 GHz, 5 GHz) and millimeter wave (e.g., 30 GHz, 60 GHz) bands.

[0067] The communication unit (210) transmits and receives signals as described above. Accordingly, the communication unit (210) may be referred to as a transmitter, a receiver, or a transceiver. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the communication unit (210).

[0068] According to various embodiments, the communication unit (210) may receive a signal for channel estimation. Additionally, the communication unit (210) may feed back channel information (e.g., channel state information (CSI)) generated by the processing unit (220) described later to another device (e.g., the transmitting device 110 of FIG. 1). Additionally, the communication unit (210) may receive data generated according to the channel information fed back to the other device.

[0069] Additionally, through the communication unit (210), the receiving device (120) can perform signaling with the transmitting device (110) to determine a receiving technique. For example, through signaling, at least one of information about a coded modulation method, information about a bit-to-symbol mapping method, information indicating the degree of change of the channel, and information indicating the channel correlation of the MIMO channel can be exchanged.

[0070] In performing operations according to various embodiments of the present invention, at least some of the operations of the communication unit (210) may be controlled by the processing unit (220) described below. At this time, at least some of the processing unit (220) may be configured to be included in the communication unit (210). The processing unit (220) can control the overall operations of the receiving device (120). For example, the processing unit (220) can transmit and receive signals through the communication unit (210). According to one embodiment, the processing unit (220) receives a control signal from at least one transmitting device, processes the received control signal to generate channel information (e.g., channel state information (CSI)) for each transmitting device, and feeds back the generated channel information to the transmitting device.

[0071] Additionally, the processing unit (220) can write and read data to the storage unit (230). To this end, the processing unit (220) may include at least one processor or microprocessor, or be configured as part of a processor. Additionally, part of the communication unit (210) and the processing unit (220) may be referred to as a communication processor.

[0072] The processing unit (220) can be operabably coupled with the communication unit (210) and the storage unit (230). The processing unit (220) can process the operations of the receiving device (120) according to various embodiments by controlling the communication unit (210) and the memory (230).

[0073] According to one embodiment of the present invention, the processing unit (220) can perform the operation of the communication unit (210) or control the communication unit (210) to operate. At this time, the processing unit (220) may be configured independently of the communication unit (220), but may be configured to be included in the communication unit (210) as described above. When the processing unit (220) is configured to be included in the communication unit (210), the processing unit (220) may be additionally configured outside the communication unit (210).

[0074] The storage unit (230) can store data such as a basic program, an application program, and setting information for the operation of the receiving device (120). The storage unit (230) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (230) may provide stored data upon request from the processor (220). According to various embodiments, the memory (230) may store precoders to feed back channel information to the transmitting device 110.

[0075] Although the electronic device (200) of FIG. 2 was described as having the configuration of a receiving device (120) as an example, it was explained that the communication unit (210) can be configured to include not only a receiver but also a transmitter. In this case, if the receiving device (120) is configured as a base station, a backhaul communication unit that provides an interface for communicating with a backhaul network may be further included.

[0076] Likewise, according to various embodiments of the present invention, it is obvious that the communication unit (210) of the electronic device (200) can also be applied to the transmitting device (120) when the communication unit (210) is configured to include a transmitter.

[0077] FIG. 3 illustrates a communication unit configuration including a transmitter of an electronic device in a wireless communication system according to one embodiment of the present invention.

[0078] Referring to FIG. 3, the communication unit of the electronic device (200) may be configured to include at least one transmitter (301). The transmitter (301) may be configured as a device that generates ð / 2 phase-shifted binary phase shift keying (BPSK) (hereinafter, ð / 2-BPSK), ð / 2 phase-shifted pulse amplitude modulation (PAM) (hereinafter, ð / 2-PAM), quadrature phase shift keying (QPSK), or quadrature amplitude modulation (QAM) symbols. For example, it may be a transmitter configuration included in the communication unit of a transmitting device (110) or a receiving device (120).

[0079] According to one embodiment, the transmitter (301) may be configured to include a DFT-spread OFDM transmitter structure. For example, the transmitter (301) may be configured to include a serial / parallel (s / p) converter (310), a first modulation unit (320), a second modulation unit (330), and a code generator (340).

[0080] The s / p conversion unit (310) converts the input data into parallel data signals. In this case, the s / p conversion unit (310) can separate the input data using an algorithm determined according to the type of data and spatial modulation rate, etc.

[0081] The first modulation unit (320) can generate modulation symbols by modulating parallel data signals input as a data modulator, and the second modulation unit (330) can generate OFDM symbols by selecting a channel symbol function corresponding to the modulation symbols as a channel modulator.

[0082] According to FIG. 3, the first modulation unit (320) and the second modulation unit (330) are shown to perform M-point DFT and N-point IDFT, respectively, but are not limited thereto and can generate modulation signals according to various methods. For example, the first modulation unit (320) and the second modulation unit (330) may be configured to generate ð / 2-BPSK, ð / 2-PAM, QPSK, or QAM symbols.

[0083] Additionally, although the transmitter (301) describes a modulation unit composed of a first modulation unit (320) and a second modulation unit (330), it may be configured to include one modulation unit or three or more modulation units.

[0084] The code generation unit (340) can generate and insert a cyclic code (e.g., cyclic prefix, CP) to maintain the subcarrier orthogonality of the OFDM transmission method and transmit a signal through an antenna.

[0085] According to one embodiment, the signal transmitted through the transmitting device (110) may include a signal to which frequency domain spectrum shaping (FDSS) is applied.

[0086] FIG. 4 illustrates a communication unit configuration including a receiver of an electronic device in a wireless communication system according to one embodiment of the present invention.

[0087] Referring to FIG. 4, the operation of a receiving device (120) receiving a signal transmitted from at least one transmitting device (110) can be described. At this time, the communication unit of the receiving device (120) may be configured to include at least one receiver (401). The receiver (401) receives a signal transmitted from at least one transmitting device through a plurality of antennas. At this time, the receiver (401) may be configured as a receiver that processes OFDM symbols. For example, the receiver (401) may be configured to process at least one symbol among ð / 2-BPSK, ð / 2-PAM, linear phase-shifted BPSK, linear phase-shifted PAM, QPSK, or QAM. For example, the receiver (401) may be a receiver configuration included in the communication unit of the transmitting device (110) or the receiving device (120).

[0088] According to one embodiment, the receiver (401) may be configured to include a DFT-spread OFDM receiver structure. For example, the receiver (401) may be configured to include at least one antenna (410), a preprocessing unit (420), an alignment unit (430), a decomposition unit (440), an estimation unit (450), and a combination unit (460).

[0089] According to one embodiment, the antenna (410) can receive a signal transmitted from at least one transmitting device (110). At this time, the antenna (410) may be included in a plurality of receiving devices (120), and the signal transmitted from the transmitting device (110) can be received through at least one of the plurality of antennas included in the receiving device (120).

[0090] The preprocessing unit (420) performs an operation to process the received signal so that channel estimation is possible. According to one embodiment, the preprocessing unit (420) may include at least one component among a code removal unit (421) that removes the CP of the received signal, a modulation unit (423) that performs N-point DFT, and a selection unit (425) that determines a resource block (RB). The received signal can be processed through the preprocessing unit (420) into a vector component for use in symbol estimation. For example, the preprocessing unit (420) can output the symbols included in the received signals received through the antenna as a vector component.

[0091] The alignment unit (430) can align the symbols of the received signal. At this time, the alignment unit (430) generates an aligned vector by arranging (or stacking) the vector components of the received signal symbols, and the decomposition unit (440) can perform decomposition for each of the aligned vector components to convert them into a specific symbol.

[0092] According to one embodiment, the decomposition unit (440) can convert QPSK or QAM symbols into BPSK or PAM symbols by performing ð / 2-PAM decomposition on them.

[0093] The estimation unit (450) performs symbol estimation on aligned symbols including transformed symbols. At this time, the estimation unit (450) may estimate BPSK or PAM symbols based on a low-complexity optical linear MMSE estimator proposed according to an embodiment of the present invention. At this time, aligned symbols and their conjugate values ​​may be input to the estimation unit (450), and a conjugate operation unit (470) may be included for this purpose.

[0094] The combining unit (450) can estimate the symbol vector of the received signal by synthesizing QPSK or QAM symbols from the estimated BPSK or PAM symbols.

[0095] The receiving device (120) has significantly reduced computational complexity by applying a low-complexity optical linear MMSE estimator according to one embodiment of the present invention described above, and thus can rapidly perform data symbol estimation of the signal. Below, the signal reception of the receiving device (120) will be explained in detail through drawings and mathematical formulas.

[0096] FIG. 5 shows the operation of receiving a signal transmitted from a transmitting device in a receiving device according to one embodiment of the present invention.

[0097] According to one embodiment, the signal received by the receiving device (120) can be expressed as [Equation 1].

[0098]

[0099] Here, Y represents a signal received by the receiving device (120), and X represents a signal transmitted by the transmitting device (110). Here, the transmitting device (110) can transmit signal X by applying FDSS to the signal as described above in order to reduce the peak-to-average power ratio (PAPR).

[0100] H represents the channel between the transmitting device (110) and the receiving device (120). Z represents the noise between the channels. The antenna of the transmitting device 110 It is a dog, and the antenna of the receiving device 120 In the case of an individual, X is It is a vector of size x 1, and Y and Z are It is a vector of size x 1, and H is x It can be a matrix of size

[0101] According to various embodiments of the present invention, a linear MMSE estimator for low-complexity light and a linear receiver for low-complexity light including the same can be proposed for more effectively estimating a signal X.

[0102] Generally, a linear optical receiver is very complex because it calculates the inverse of a 2MNr x 2MNr matrix to apply to the channel matrix H of the received signal in order to estimate the signal transmitted by the transmitting device (110). In addition, as can be seen in FIG. 11, there is a very large difference in the number of multiplications required to calculate the inverse matrix.

[0103] On the other hand, the low-complexity optical linear MMSE estimator proposed in the present invention is applied to the channel matrix H of the received signal. matrix of size It is provided to perform translation inverse matrix calculation, so the complexity of calculating the inverse of the channel matrix H can be significantly reduced.

[0104] According to one embodiment, in order to apply a low-complexity light linear MMSE estimator, it is necessary to satisfy the condition that k in [Equation 2] is an integer.

[0105]

[0106] Here, f Is f A phase transition value satisfying ∈[0 ð], for example - In the case of BPSK f =ð / 2 and M is ( is the number of assigned sub-carriers satisfying (an arbitrary natural number). Here, f A phase shift satisfying ∈[0 ð] may include a linear phase shift.

[0107] For example, in the case of ð / 2-BPSK considered in 5G, the constellation rotation angle f =ð / 2. Applying this, M satisfying the condition that k is an integer is a multiple of 4, and the constellation rotation angle f Since the number of assignable subcarriers when =ð / 2 includes cases where it is a multiple of 12, it can satisfy the conditions for applying a low-complexity, light-linear MMSE estimator.

[0108] To this end, the receiving device (120) can determine the modulation method of the symbols, whether the received signals are modulated based on at least one designated modulation scheme among various modulation schemes.

[0109] For example, if the receiving device (120) is a base station, the receiving device (120) can determine whether the symbol included in the received signal is a ð / 2-BPSK, ð / 2-PAM, QPSK, or QAM symbol based on the pilot signal received from the transmitting device (110). On the other hand, if the receiving device (120) is a terminal, the receiving device (120) can determine whether the symbol included in the received signal is a ð / 2-BPSK, ð / 2-PAM, QPSK, or QAM symbol based on the control information of the signal received from the transmitting device (110).

[0110] That is, the present invention may provide a receiver (hereinafter, a linear receiver of low-complexity light) that includes a linear MMSE estimator of low-complexity light, in which computational complexity is significantly reduced when the signal transmitted and received between the transmitting device (110) and the receiving device (120) uses ð / 2-BPSK, ð / 2-PAM, QPSK, or QAM symbols.

[0111] As described above, when the signal received through each of the multiple antennas (511, 513, 515) is processed through the preprocessing unit (420) and the result is examined in units of symbols, it can be expressed as [Equation 3].

[0112]

[0113] is a symbol vector after the signal received through the i-th receiving antenna of the receiving device (120) has been processed through the preprocessing unit (420). According to one embodiment, it may be a vector representing the received signal symbols after CP removal, N-point DFT, and RB selection operations have been performed on the symbols included in the received signal.

[0114] is the symbol vector of MХ1 data from the k-th transmitting antenna. Here, the k-th transmitting antenna may be the antenna of the k-th transmitting device, or the k-th antenna of a single transmitting device, or an arbitrarily distinguished number for multiple antennas.

[0115] is the MХM channel matrix between the k-th transmitting antenna and the i-th receiving antenna.

[0116] is the noise vector at the i-th receiving antenna.

[0117] The receiving device (120) is a symbol vector determined through the selection unit (425). Symbol estimation can be performed based on the fields. To this end, the receiving device (120) can align the determined symbol vectors.

[0118] FIG. 6 illustrates the operation of aligning signals in a receiving device according to one embodiment of the present invention.

[0119] Referring to FIG. 6, the receiving device (120) can align the preprocessed symbol vector through the alignment unit (430).

[0120] According to one embodiment, the alignment unit (430) receives input signals ( , , 쪋, ) can be stacked into a single long vector (in the horizontal or column direction). According to one embodiment, the alignment unit (430) may generate an aligned vector by sequentially listing the symbol vectors of the input received signal, or may generate an aligned vector by distinguishing them according to the modulation method of the symbols. Alternatively, the alignment unit (430) may align the symbols of the received signal by distinguishing them according to the receiving antenna receiving the signal or the transmitting antenna of the signal identified from the received signal. Here, generating an aligned vector may involve storing each signal as a vector in the storage unit (230). The aligned symbols of the received signal may be processed through vector matrix operations in subsequent operations.

[0121] A sorted vector r can be expressed as in [Equation 4].

[0122]

[0124] Here, Is It is the number of transmitter antenna components satisfying, and silver It is the number of receiver antenna components satisfying, and K is The number of ð / 2-BPSK symbol vectors satisfying, and in the case of imperfect symbols , in the case of a proper symbol Here, non-eigensignals can be defined to include ð / 2 phase-shifted signals such as ð / 2-BPSK, ð / 2-PAM, etc., and eigensignals can be defined to include QPSK or QAM.

[0125] The channel matrix H of [Equation 4] can be expressed as in [Equation 5].

[0126]

[0127] Here, each block component of the channel matrix H is an M / X / M diagonal matrix, and is the M / X M channel diagonal matrix between the j-th transmitting antenna and the i-th receiving antenna.

[0128] of [Mathematical Formula 4] It can be expressed as [Equation 6].

[0129]

[0130] is an MХM DFT matrix, and is an M / M identity matrix, and is an M x M all-zero matrix.

[0131] Star rotation matrix of [Equation 4] It is equal to [Mathematical Formula 7].

[0132]

[0133] According to [Equation 7], the star rotation matrix R can be composed of an M x M diagonal matrix with the pattern 1, j, -1, -j, 1, ��.

[0134] In this case, the channel matrix H may include the effect of the transmitter's FDSS. For convenience, the first K symbol vectors are non-eigensignals, and the rest The dog is the QPSK or QAM symbol.

[0135] Symbol estimation according to one embodiment of the present invention includes a low-complexity optical linear MMSE estimator when the received signal satisfies [Equation 1], and thus an operation to process symbol conversion of the received signal can be performed.

[0136] The receiving device (120) can convert symbol vectors that are QPSK or QAM symbols.

[0137] FIG. 7 illustrates the operation of converting the symbol of a signal in a receiving device according to one embodiment of the present invention.

[0138] Referring to FIG. 7, the receiving device (120) has aligned symbol vectors r Symbol transformation can be performed on vectors of specific symbols.

[0139] The decomposition unit (440) of the receiving device (120) can convert QPSK or QAM symbols into BPSK or PAM symbols (711). The component conversion of the symbols can be performed through ð / 2-PAM decomposition, and according to one embodiment, the symbol conversion performed for the i-th QPSK or QAM symbol can be expressed as [Equation 8].

[0140]

[0141] According to one embodiment, the ð / 2-PAM decomposition of the decomposition unit (440) performed based on [Equation 8] may be a decomposition of the QPSK or QAM symbol vector of the aligned vector r into a real part and an imaginary part, respectively.

[0142] According to one embodiment, the decomposition unit (440) can align the symbol vectors of the signal received through the i-th antenna to have a specific pattern by combining and / or rearranging at least some of the real and imaginary parts of the QPSK or QAM symbol vectors.

[0143] For example, referring to [Equation 4] and [Equation 8], the decomposition unit (440) is d which are QPSK or QAM symbols among the aligned received signal symbols. i The real and imaginary parts of were each processed into a state where the components of the constellation rotation matrix R could be extracted and substituted, and each of the real and imaginary parts , Symbols containing can be treated as ð / 2-PAM symbols.

[0144] Referring to [Equation 8], d, which are QPSK or QAM symbols i It can be confirmed that the real and imaginary parts of each are arranged so that the pattern 1, j, -1, -j, 1, 쪋 of the constellation rotation matrix R is extracted.

[0145] That is, the decomposition unit (440) can decompose one eigenvalue into two non-eigenvalues ​​through ð / 2-PAM decomposition. The decomposition unit (440) can perform symbol transformation by substituting the real and imaginary parts of the symbols of the aligned QPSK or QAM, respectively, with the star rotation matrix R component, and decomposing the substituted real and imaginary parts into two ð / 2-PAM symbols.

[0146] The decomposition unit (440) rearranges the converted ð / 2-PAM symbol vector to form a newly arranged vector consisting only of the original received ð / 2-PAM, ð / 2-BPSK, BPSK, PAM, linear phase shifted BPSK, or linear phase shifted PAM symbols and the converted ð / 2-PAM symbols. Creates.

[0147] According to the above description, conversion of QPSK or QAM symbols into ð / 2-PAM symbols is disclosed, but is not limited thereto, and conversion into ð / 2-BPSK symbols may also be performed through an operation identical or similar to the operation of the decomposition unit (440) described above.

[0148] According to one embodiment, a newly aligned vector after ð / 2-PAM decomposition It can be expressed as [Equation 9].

[0149]

[0150] At this point, a new channel matrix for processing ð / 2-PAM symbols , and the linearly phase-shifted matrix (i.e., reflecting the star rotation matrix R of [Equation 7]). is equal to [Equation 10] and [Equation 11], respectively.

[0151]

[0152] Here, Is and Satisfying, Is and Satisfying, Is and Satisfies.

[0153]

[0154] Here, is an MХM DFT matrix, and R is a star rotation matrix, and is an M / M all-zero matrix. According to one embodiment, matrix P is a newly sorted vector The symbols of and It can be a permutation matrix to be composed of the components of. Referring to [Equation 11], matrix P can be composed of a block diagonal matrix of a star rotation matrix.

[0155] According to one embodiment of the present invention, the non-genuine symbols of the received signal and the symbols converted into non-genuine symbols may include a block diagonal matrix in their components. The receiving device (120) has a newly aligned symbol vector Based on features including this block diagonal matrix, BPSK or PAM symbols can be estimated.

[0156] FIG. 8 illustrates the operation of estimating a symbol vector in a receiving device according to one embodiment of the present invention.

[0157] Referring to FIG. 8, the estimation unit (450) is a newly aligned vector Low-complexity broad linear MMSE estimator from BPSK or PAM symbol vectors estimated using Creates (811).

[0158] At this time, low-complexity light linear MMISE estimator is a newly sorted vector and its conjugate value This is input, and the estimated BPSK or PAM symbol vector It can be expressed as [Mathematical Equation 12].

[0159]

[0160] Low-complexity broad linear MMSE estimator To determine , a substitution formula based on [Equation 9] is applied, and the substituted matrix It can be expressed as [Mathematical Equation 13].

[0161]

[0162] Therefore, [Equation 9] is the new channel matrix of [Equation 13] and a matrix reflecting linear phase shift It can be expressed as shown in [Equation 14] below by substituting.

[0163]

[0164] From [Equation 14], the low-complexity optical linear MMSE estimator proposed in the present invention It can be determined to perform the operation of [Equation 15].

[0165]

[0166] Here, is an MХM IDFT matrix, and can be determined through a method identical or similar to [Equation 6]. According to one embodiment of the present invention, a low-complexity optical linear MMSE estimator The inverse matrix constituting may include a diagonal matrix in at least one block. Referring to [Equation 15], the low-complexity, light linear MMSE estimator Based on diag{}, it can be confirmed that the inverse matrix constituting consists of each block as a diagonal matrix. Here, The component is a low-complexity, light-linear MMSE estimator It can be determined based on the noise component z in the symbols input to.

[0167] That is, the low-complexity light linear MMSE estimator of the estimation unit (450). is a permutation matrix composed of block diagonals. P and new channel matrix matrix for It may include an inverse matrix for application. Thus, the received signal symbols according to [Equation 9], [Equation 13], and [Equation 14], and the low-complexity broad linear MMSE estimator according to [Equation 15] Based on, the estimation unit (450) estimates the symbols , and It can output.

[0168] Here, included in the inverse matrix of [Equation 15] vector and Vectors can be expressed as [Equation 16] and [Equation 17], respectively.

[0169]

[0170] At this time class It is as follows.

[0171]

[0172]

[0173] Here, is an M / XM identity matrix, and performs a downshift of the rows of matrix A by k. Here, silver In the case where the number of assigned subcarriers in [Equation 2] satisfies a multiple of 4 f The value, for example, ð / 2, the constellation rotation angle of a BPSK symbol f By applying it to [Equation 16], it can be defined as follows.

[0174]

[0175] At this time and is as follows.

[0176]

[0177]

[0178] Here, is an M / M identity matrix, and the circshift(A,k) matrix performs a downshift of the rows of A by k, and flipud( )Is A function that inverts can be represented. Here, Is In the case where the number of assigned subcarriers in [Equation 2] satisfies a multiple of 4 f The value, for example, ð / 2, the constellation rotation angle of a BPSK symbol f By applying it to [Equation 17], it can be defined as follows.

[0179] As mentioned earlier, the existing optical linear MMSE estimator is The inverse matrix of size must be calculated. On the other hand, the inverse matrix of the low-complexity light linear MMSE estimator proposed based on [Mathematics Sheet 15] can be configured such that each matrix block contains a block matrix with a diagonal matrix when the number of assigned subcarriers of the received signal satisfies a multiple of 4.

[0180] In other words, the symbol estimation of the optical linear MMSE estimator is the existing Not the inverse matrix calculation for a channel matrix H of size M, but for a matrix of size M / M Since the inverse matrix can be calculated, the complexity of the inverse matrix calculation can be significantly reduced.

[0181] The determinant of the linear MMSE estimator of low-complexity optical can be determined according to the channel environment, i.e., when the number of assigned subcarriers of the received signal satisfies a multiple of 4. For example, the block diagonal matrix included in the inverse matrix operation of the linear MMSE estimator of low-complexity optical can be determined according to the number of ð / 2-BPSK, QPSK, and QAM signals among the signals received through the multiple antennas of the receiving device (120).

[0182] At this time, low-complexity light linear MMSE estimator It can be newly determined whenever the channel environment changes or according to a specified period. Or, depending on the selection of the processing unit (220), a linear MMSE estimator of low-complexity light It may be decided.

[0183] FIG. 9 illustrates the operation of converting the symbol of an estimated received signal in a receiving device according to one embodiment of the present invention.

[0184] Referring to FIG. 9, the receiving device (120) has an estimated BPSK or PAM symbol vector Symbol transformation can be performed on vectors of specific symbols. According to one embodiment, the combining unit (460) is a QPSK or QAM symbol synthesis unit, and among the estimated symbols, ð / 2-BPSK or ð / 2-PAM symbols identified as having undergone ð / 2-PAM decomposition in the decomposition unit (440), i.e. and Synthesize it again into QPSK or QAM (911).

[0185] ð / 2-BPSK or ð / 2-PAM symbols, that is and A vector synthesized from QPSK or QAM symbols It can be expressed as [Mathematical Equation 18].

[0186]

[0187] [Mathematical Equation 8] and the operation of the decomposition unit (440) together, the combination unit (460) can determine the real part and the imaginary part decomposed from the QPSK or QAM symbol vector among the estimated symbols into the ð / 2-PAM symbol vector, and perform the operation of combining the real part and the imaginary part to convert them into QPSK or QAM symbols.

[0188] According to one embodiment, the combining unit (460) can identify the decomposed real part or decomposed imaginary part of the QPSK symbol or QAM symbol before conversion for the ð / 2-BPSK or ð / 2-PAM symbol among the estimated symbol vectors. At this time, the combining unit (460) can apply a constellation rotation matrix R to the estimated ð / 2-BPSK or ð / 2-PAM symbol and combine the corresponding real part and imaginary part to convert it into the estimated QPSK symbol or QAM symbol.

[0189] In other words, a vector composed of QPSK or QAM symbols is the ð / 2-PAM symbol vector estimated through [Equation 12] and It can be calculated using, and according to one embodiment, the symbol conversion according to [Equation 18] may be the reverse processing of the symbol conversion of [Equation 8]. For example, of [Equation 18] , and Each is d of [Equation 8] i. and It can be substituted at the position of. The joining part (460) processes the substituted [Equation 8] in reverse order. It can be calculated. The finally estimated symbol vector It can be expressed as [Equation 19].

[0190]

[0191] In other words, the estimated symbol vector It can be represented as a vector in which the estimated received signal symbols are aligned.

[0192] The receiving device (120) can significantly improve the processing speed by estimating data symbols as described above, and thus can greatly improve the processing performance of the received signal.

[0193] FIG. 10 is a diagram comparing the processing of a conventional linear optical receiver and a low-complexity linear optical receiver proposed in the present invention in a receiving device according to one embodiment of the present invention.

[0194] According to FIG. 10, the graph shows the complexity of the inverse matrix of the linear optical receiver (y-axis) relative to the number of antennas (x-axis) of the receiving device (120), and it can be seen that the computational complexity is significantly reduced when estimating the symbol of a signal through the low-complexity linear optical receiver (2) proposed in the present invention.

[0195] FIG. 11 is a drawing showing the main configuration of a receiver of a receiving device according to one embodiment of the present invention.

[0196] The receiver of the receiving device (120) can be represented as a receiver of low-complexity linear light (1100) including an MMSE estimator of low-complexity linear light.

[0197] According to one embodiment, a receiver (1100) may include an alignment unit (430) that generates an aligned vector by arranging (or stacking) signals received through an antenna, a decomposition unit (440) that converts QPSK or QAM symbols of the aligned vector into BPSK or PAM symbol vectors by performing ð / 2-PAM decomposition on them, an estimation unit (450) that estimates the symbols of the received signal using a low-complexity optical linear MMSE estimator proposed through the present invention, and a combination unit (460) that synthesizes the ð / 2-BPSK or ð / 2-PAM symbols, which are the results estimated by the estimation unit (450), back into QPSK or QAM.

[0198] Additionally, the communication unit (210) may further include a conjugate operation unit (470) for generating a conjugate value of a symbol vector in the input of the estimation unit (450). Furthermore, the communication unit (210) may further include a preprocessing unit (420) comprising at least one component of a code removal unit (421) for removing the CP of a received signal, a modulation unit (423) for performing an IDFT on the signal from which the CP has been removed, and a selection unit (425) for determining a resource block (RB).

[0199] FIG. 12 illustrates the flow of an operation for estimating the symbol of a received signal in a receiving device according to one embodiment of the present invention.

[0200] According to step 1201, the receiving device (120) receives an OFDM signal through a plurality of antennas. At this time, the receiving device (120) can receive signals transmitted from a plurality of OFDM transmitting devices.

[0201] According to various embodiments of the present invention, a signal received by a receiving device (120) through a plurality of antennas may include a signal using ð / 2-BPSK, ð / 2-PAM, QPSK, or QAM symbols. According to one embodiment, a receiving device (120) receiving a signal in a wireless communication environment in which at least one of ð / 2-BPSK symbols and ð / 2-PAM symbols, and at least one of QPSK symbols or QAM symbols are mixed and transmitted and received may be assumed.

[0202] Additionally, the signal received by the receiving device (110) may be a signal from the transmitting device (110) to which the FDSS effect has been applied.

[0203] According to step 1203, the receiving device (120) aligns the received signal symbols included in the received signals. The receiving device (120) may stack or list the received signal symbols as a vector. According to one embodiment, the receiving device (120) preprocesses the symbol vector The items can be sorted into vector r.

[0204] According to step 1205, the receiving device (120) converts the aligned received signal symbols. According to one embodiment, the receiving device (120) may perform symbol conversion on QPSK or QAM symbols included in the symbol vector r of the aligned received signal. The receiving device (120) may perform ð / 2-PAM decomposition to convert the unique symbols, QPSK or QAM symbols, into non-unique symbols, ð / 2-PAM or ð / 2-BPSK symbols. For example, the receiving device (120) converts the received signal symbol d received at the i-th antenna among the aligned QPSK or QAM symbols. i The constellation rotation matrix R component can be extracted and substituted from each of the real part and the imaginary part. The receiving device (120) can output each of the substituted real part and the imaginary part as two ð / 2-PAM or ð / 2-BPSK symbols.

[0205] The receiving device (120) uses the previously aligned receiving signal symbols including the symbol-converted vectors to create a newly aligned symbol vector of the receiving signal. It can generate.

[0206] According to step 1207, the receiving device (120) can estimate the data symbols of the aligned received signal symbols. According to one embodiment, the receiving device (120) has a newly aligned vector The low-complexity optical linear MMSE estimator proposed in the present invention Apply to the ð / 2-PAM or ð / 2-BPSK symbol vector It can be estimated.

[0207] Low-complexity broad linear MMSE estimator When the received signal satisfies the specified conditions as described above, each matrix block is configured to include an inverse matrix consisting of a block diagonal matrix, and data symbols can be estimated by applying a low-complexity optical linear MMSE estimator to the ð / 2-BPSK symbols, ð / 2-PAM decomposed QPSK symbols, and QAM symbols of the received signal as described above.

[0208] The receiving device (120) is the symbol vector of the converted received signal. The data can be estimated. In this case, a low-complexity, broad linear MMSE estimator The inverse matrix in which each matrix block consists of a block diagonal matrix is, as described above It is applied to the channel matrix, and more specifically, to the permutation matrix composed of a block diagonal matrix by referring to [Equation 13] and [Equation 14]. P and channel matrix matrix for It can be applied to.

[0209] Here, the specified condition is when the received signal satisfies the case where the number of assigned subcarriers in [Equation 2] is a multiple of 4. f As a value, in the case of 5G f Since the number of assignable subcarriers is a multiple of 12 when =ð / 2, a low-complexity broad linear MMSE estimator The conditions for applying can be satisfied. That is, when receiving a signal containing ð / 2-BPSK symbols, such as in a 5G wireless communication environment, a low-complexity optical linear estimator including an inverse matrix in which each matrix block consists of a block diagonal matrix as described above can be provided.

[0210] According to step 1209, the receiving device (120) can convert at least some of the previously converted symbols among the estimated symbols into ð / 2-PAM symbols or ð / 2-BPSK symbols. According to one embodiment, the receiving device (120) receives the estimated BPSK or PAM symbol vector The vector estimated for the received signal by synthesizing the symbols with a history of transformation based on ð / 2-PAM decomposition back into QPSK or QAM symbols can decide.

[0211] For example, the receiving device (120) can perform the operation of converting the real and imaginary parts of the converted symbols into QPSK or QAM symbols by recombining them based on the fact that the real and imaginary parts are each decomposed into ð / 2-PAM symbols through ð / 2-PAM decomposition in step 1205.

[0212] According to step 1211, the receiving device (120) has an estimated received signal symbol vector including symbols for which symbol synthesis was performed as described above. It can be determined as the data symbol of the received signals.

[0213] As described above, various embodiments of the present invention have been explained in detail with reference to the drawings. According to various embodiments of the present invention, a receiving device method of a wireless communication system comprises: receiving orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; aligning received signal symbols included in the received signals; converting at least one quadrature phase shift keying (QPSK) symbol or quadrature amplitude modulation (QAM) symbol among the aligned received signal symbols into π / 2 phase-shifted pulse amplitude modulation (PAM) symbols; estimating data symbols of the aligned received signal symbols including the at least one converted received signal symbol; and synthesizing at least some of the π / 2 phase-shifted PAM symbols among the estimated data symbols to convert them into the QPSK symbol or the QAM symbol. and the step of determining the estimated data symbols, including the converted QPSK symbol or the QAM symbol, as the data symbols of the received signals;

[0214] Here, the step of aligning the received signal symbols included in the above-mentioned continuously received signals can align the received signal symbols as a vector.

[0215] Here, the step of converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols may further include the step of newly aligning the received signal symbols based on the converted π / 2 phase-shifted PAM symbols.

[0216] Here, the step of estimating data symbols of the aligned received signal symbols including at least one converted received signal symbol can estimate the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols.

[0217] Here, the step of estimating data symbols of the aligned received signal symbols including at least one converted received signal symbol may apply the inverse of a matrix in which at least one matrix block includes a block diagonal matrix to the channel matrix of the received signal symbols based on a specified condition.

[0218] Here, the specified condition is that at least one symbol among the received signals is in the following mathematical formula,

[0219]

[0220] (Here, f Is f The phase transition value M satisfying ∈[0 ð] is The number of allocated subcarriers satisfying, is an arbitrary natural number, k is an integer)

[0221] In the above case, M may satisfy the condition of being a multiple of 4.

[0222] Here, the step of converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols may include the step of substituting at least one QPSK symbol or QAM symbol among the aligned received signal symbols so that a constellation rotation matrix is ​​extracted, and determining at least a portion of each of the real part and the imaginary part of the substituted QPSK symbol or QAM symbol as the π / 2 phase-shifted PAM symbols.

[0223] Here, the step of converting the π / 2 phase-shifted PAM symbol among the estimated data symbols into the QPSK symbol or the QAM symbol may include: the step of determining the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion among the π / 2 phase-shifted PAM symbols of the estimated data symbols; and the step of combining the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion.

[0224] Here, the step of determining the real and imaginary parts of the QPSK symbol or QAM symbol before transformation among the π / 2 phase-shifted PAM symbols of the estimated data symbols may further include the step of applying the constellation rotation matrix to each of the real and imaginary parts of the QPSK symbol or QAM symbol before transformation.

[0225] Here, the specified condition is that the received signals may include at least one ð / 2-BPSK symbol.

[0226] According to various embodiments of the present invention, a receiving device of a wireless communication system comprises: at least one receiver that receives orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; and at least one processing unit functionally coupled with the at least one receiver. and a storage unit for storing the processing results of the processing unit; wherein the at least one processing unit aligns the received signal symbols included in the received signals received at any time, converts at least one quadrature phase shift keying (QPSK) symbol or quadrature amplitude modulation (QAM) symbol among the aligned received signal symbols into π / 2 phase shift pulse amplitude modulation (PAM) symbols, estimates the data symbols of the aligned received signal symbols including the at least one converted received signal symbol, synthesizes at least some of the π / 2 phase shift PAM symbols among the estimated data symbols to convert them into the QPSK symbol or the QAM symbol, and processes the estimated data symbols including the converted QPSK symbol or the QAM symbol to determine the data symbols of the received signals.

[0227] Here, the at least one processing unit can arrange the received signal symbols as a vector.

[0228] Here, the at least one processing unit can, in converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols, newly align the received signal symbols based on the converted π / 2 phase-shifted PAM symbols.

[0229] Here, the at least one processing unit can estimate the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols.

[0230] Here, the at least one processing unit, in estimating the data symbols of the aligned received signal symbols including the converted at least one received signal symbol, may apply the inverse of a matrix in which at least one matrix block includes a block diagonal matrix to the channel matrix of the received signal symbols based on a specified condition.

[0231] Here, the specified condition is that at least one symbol among the received signals is in the following mathematical formula,

[0232]

[0233] (Here, f Is f The phase transition value M satisfying ∈[0 ð] is The number of allocated subcarriers satisfying, is an arbitrary natural number, k is an integer)

[0234] In the above case, M may satisfy the condition of being a multiple of 4.

[0235] Here, the at least one processing unit, in converting at least one QPSK symbol or QAM symbol among the aligned received signal symbols into π / 2 phase-shifted PAM symbols, may substitute at least one QPSK symbol or QAM symbol among the aligned received signal symbols so that a constellation rotation matrix is ​​extracted, and determine at least a portion of each of the real part and the imaginary part of the substituted QPSK symbol or QAM symbol as the π / 2 phase-shifted PAM symbols.

[0236] Here, the at least one processing unit, in converting the π / 2 phase-shifted PAM symbol among the estimated data symbols into the QPSK symbol or the QAM symbol, determines the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion among the π / 2 phase-shifted PAM symbols of the estimated data symbols, and can combine the real part and the imaginary part of the QPSK symbol or QAM symbol before conversion.

[0237] Here, the at least one processing unit may apply the constellation rotation matrix to each of the real and imaginary parts of the QPSK symbol or QAM symbol before transformation among the π / 2 phase-shifted PAM symbols of the estimated data symbols when determining the real and imaginary parts of the QPSK symbol or QAM symbol before transformation.

[0238] Here, the specified condition is that the received signals may include at least one ð / 2-BPSK symbol.

[0239] In describing the embodiments of the present invention in detail, the communication standards defined by 3GPP will be the primary focus; however, the main gist of the present invention can be applied to other communication systems having a similar technical background with slight modifications without significantly deviating from the scope of the present invention, and this will be possible at the judgment of a person with skilled technical knowledge in the technical field of the present invention. Explanation of the symbols

[0240] 100: Wireless communication environment 110: Transmitter 120: Receiver 210: Communication unit 220: Processing unit 230: Storage unit 401: Receiver 410: Antenna 420: Preprocessing unit 430: Alignment unit 440: Decomposition section 450: Estimation section 460: Joint

Claims

Claim 1 A method performed in a receiving device of a wireless communication system, comprising: receiving orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; aligning received signal symbols included in the received OFDM signals; obtaining converted received signal symbols by converting quadrature phase shift keying (QPSK) symbols or quadrature amplitude modulation (QAM) symbols among the aligned received signal symbols into pulse amplitude modulation (PAM) symbols with a π / 2 phase shift; estimating data symbols of the aligned received signal symbols including the converted received signal symbols; synthesizing the data symbols of the converted received signal symbols among the estimated data symbols to convert them into data symbols of the QPSK symbols or data symbols of the QAM symbols; and determining the estimated data symbols including the data symbols of the QPSK symbols or the data symbols of the QAM symbols as data symbols of the received OFDM signals. Claim 2 A method according to claim 1, wherein the operation of aligning the received signal symbols included in the received OFDM signals comprises the operation of aligning the received signal symbols as a vector. Claim 3 A method according to claim 1, wherein the operation of obtaining the converted received signal symbols by converting the QPSK symbol or the QAM symbol into the π / 2 phase-shifted PAM symbol further includes the operation of newly aligning the received signal symbols based on the converted received signal symbols. Claim 4 A method according to claim 1, wherein the operation of estimating the data symbols of the aligned received signal symbols including the converted received signal symbols comprises the operation of estimating the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols. Claim 5 A method according to claim 1, wherein the operation of estimating the data symbols of the aligned received signal symbols including the transformed received signal symbols comprises, based on a specified condition, applying the inverse of a matrix in which at least one matrix block includes a block diagonal matrix to the channel matrix of the received signal symbols. Claim 6 In claim 5, the specified condition is that at least one of the received signal symbols is in the following mathematical formula, ( φ Is φ The phase transition value M satisfying ∈[0 π] is The number of allocated subcarriers satisfying, A method comprising the condition that M is a multiple of 4 in an arbitrary natural number (where k is an integer). Claim 7 A method according to claim 1, wherein the operation of obtaining the transformed received signal symbols by transforming the QPSK symbol or the QAM symbol among the aligned received signal symbols into the π / 2 phase-shifted PAM symbols comprises the operation of substituting the QPSK symbol or the QAM symbol among the aligned received signal symbols such that a constellation rotation matrix is ​​extracted, and obtaining at least a portion of the real part and the imaginary part of each of the substituted QPSK symbol or the substituted QAM symbol as the transformed received signal symbols. Claim 8 In claim 7, the operation of synthesizing the data symbols of the converted received signal symbols among the estimated data symbols to convert them into the data symbol of the QPSK symbol or the data symbol of the QAM symbol comprises: the operation of determining the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol among the data symbols of the converted received signal symbols; and the operation of combining the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol. Claim 9 In claim 8, the operation of determining the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol among the data symbols of the converted received signal symbols further comprises the operation of applying the constellation rotation matrix to each of the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol. Claim 10 In claim 5, the specified condition comprises a condition in which the received OFDM signals include at least one π / 2-BPSK (binary phase shift keying) symbol. Claim 11 A receiving device of a wireless communication system comprises: at least one receiver that receives orthogonal frequency division multiplexing (OFDM) signals through a plurality of antennas; at least one processing unit functionally coupled with the at least one receiver; and a storage unit that stores the processing result of the processing unit. The at least one processing unit aligns received signal symbols included in the received OFDM signals; obtains converted received signal symbols by converting quadrature phase shift keying (QPSK) symbols or quadrature amplitude modulation (QAM) symbols among the aligned received signal symbols into pulse amplitude modulation (PAM) symbols with a π / 2 phase shift; estimates data symbols of the aligned received signal symbols including the converted received signal symbols; and synthesizes the data symbols of the converted received signal symbols among the estimated data symbols to convert them into data symbols of the QPSK symbols or data symbols of the QAM symbols. A receiving device configured to determine the estimated data symbols, including the data symbol of the QPSK symbol or the data symbol of the QAM symbol, as the data symbols of the received OFDM signals. Claim 12 In claim 11, the receiving device, wherein at least one processing unit is configured to align the received signal symbols as a vector. Claim 13 A receiving device according to claim 11, wherein the at least one processing unit is configured to obtain the converted received signal symbols by converting the QPSK symbol or the QAM symbol into the π / 2 phase-shifted PAM symbol, and to newly align the received signal symbols based on the converted received signal symbols. Claim 14 A receiving device according to claim 11, wherein the at least one processing unit is configured to estimate the data symbols based on the aligned received signal symbols and the conjugate values ​​of the aligned received signal symbols. Claim 15 A receiving device according to claim 11, wherein the at least one processing unit is configured to apply the inverse of a matrix containing a block diagonal matrix to the channel matrix of the received signal symbols based on a specified condition in estimating the data symbols of the aligned received signal symbols including the transformed received signal symbols. Claim 16 In claim 15, the specified condition is that at least one of the received signal symbols is in the following mathematical formula, ( φ Is φ The phase transition value M satisfying ∈[0 π] is The number of allocated subcarriers satisfying, A receiving device comprising the condition that M is a multiple of 4 in (where k is an arbitrary natural number and k is an integer). Claim 17 A receiving device according to claim 11, wherein the at least one processing unit is configured to obtain the transformed receiving signal symbols by transforming the QPSK symbol or the QAM symbol among the aligned receiving signal symbols into the π / 2 phase-shifted PAM symbols, wherein the QPSK symbol or the QAM symbol among the aligned receiving signal symbols is substituted so that a constellation rotation matrix is ​​extracted, and at least a portion of each of the real part and the imaginary part of the substituted QPSK symbol or the substituted QAM symbol is obtained as the transformed receiving signal symbols. Claim 18 A receiving device according to claim 17, wherein the at least one processing unit is configured to synthesize the data symbols of the converted receiving signal symbols among the estimated data symbols to convert them into the data symbol of the QPSK symbol or the data symbol of the QAM symbol, determine the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol among the data symbols of the converted receiving signal symbols, and combine the real part and the imaginary part for the data symbol of the QPSK symbol or the data symbol of the QAM symbol. Claim 19 A receiving device according to claim 18, wherein the at least one processing unit is configured to apply the constellation rotation matrix to each of the real part and the imaginary part for the data part of the QPSK symbol or the data part of the QAM symbol among the data symbols of the converted received signal symbols. Claim 20 A receiving device according to claim 15, wherein the specified condition comprises the condition that the received OFDM signals include at least one π / 2-BPSK (binary phase shift keying) symbol.

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