Electronic device, control method, and program

Abstract

This electronic device transmits and receives radio waves by a time division duplex system. The electronic device comprises: a transmission unit provided with at least one antenna; a reception unit provided with at least one antenna; a channel estimation unit; and a correction value calculation unit. The channel estimation unit estimates a first channel matrix that is the channel matrix of a first channel directed from the transmission unit to the reception unit, and a second channel matrix that is the channel matrix of a second channel directed from the reception unit to the transmission unit. The correction value calculation unit calculates a correction value for establishing the reciprocity between the first channel and the second channel on the basis of the difference between the first channel matrix and the second channel matrix.

Description

Electronic device, control method, and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-197732, filed on November 21, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to an electronic device, a control method, and a program.

[0003] Beamforming (hereinafter also referred to simply as "BF") technology is known in wireless communication devices equipped with phased array antennas including multiple antenna elements, which transmit radio waves toward a specific direction or receive radio waves from a specific direction. Known BF technologies include digital BF, analog BF, and hybrid BF. Furthermore, calibration techniques have been proposed to effectively perform BF, correcting the phase and / or amplitude of transmitted or received radio waves. For example, Patent Document 1 discloses a calibration method for a wireless communication device that supports hybrid BF by incorporating a calibration transmitting and receiving antenna. Patent Document 2 also discloses a wireless communication device that calibrates distributed antennas.

[0004] Patent Publication No. 2022-525624 International Publication No. 2022 / 130821

[0005] An electronic device according to one embodiment is an electronic device that transmits and receives radio waves using a time division duplex method, and includes: a transmitting unit having at least one antenna; a receiving unit having at least one antenna; a channel estimating unit that estimates a first channel matrix that is a channel matrix of a first channel directed from the transmitting unit to the receiving unit, and a second channel matrix that is a channel matrix of a second channel directed from the receiving unit to the transmitting unit; and a correction value calculating unit that calculates a correction value that establishes reciprocity between the first channel and the second channel based on the difference between the first channel matrix and the second channel matrix.

[0006] According to one embodiment, there is provided a control method for an electronic device that transmits and receives radio waves using a time division duplex system. The electronic device includes a transmitter having at least one antenna and a receiver having at least one antenna. The control method includes: a channel estimation step of estimating a first channel matrix that is a channel matrix of a first channel extending from the transmitter to the receiver and a second channel matrix that is a channel matrix of a second channel extending from the receiver to the transmitter; and a correction value calculation step of calculating a correction value that establishes reciprocity between the first channel and the second channel based on a difference between the first channel matrix and the second channel matrix.

[0007] According to one embodiment, a program is executed by an electronic device that transmits and receives radio waves using a time division duplex system. The electronic device includes a transmitter having at least one antenna and a receiver having at least one antenna. The program causes the electronic device to execute: a channel estimation step of estimating a first channel matrix that is a channel matrix of a first channel oriented from the transmitter to the receiver and a second channel matrix that is a channel matrix of a second channel oriented from the receiver to the transmitter; and a correction value calculation step of calculating a correction value that establishes reciprocity between the first channel and the second channel based on a difference between the first channel matrix and the second channel matrix.

[0008] FIG. 1 is a block diagram schematically showing the functional configuration of a system according to an embodiment; FIG. 2 is a block diagram schematically showing the functional configuration of an electronic device according to an embodiment; FIG. 3 is a block diagram more specifically showing the functional configuration of a part of an electronic device according to an embodiment; FIG. 4 is a block diagram more specifically showing the functional configuration of a part of an electronic device according to an embodiment;

[0009] In the present disclosure, an "electronic device" may refer to a device powered by electricity. Furthermore, a "system" may refer to a device or devices including a device powered by electricity. Furthermore, a "user" may refer to a person (typically a human) who uses a system and / or electronic device according to an embodiment. By using a system and / or electronic device according to an embodiment, a user can perform calibration with high accuracy while reducing processing costs. The system and / or electronic device according to an embodiment can reduce processing costs when performing calibration, for example, in a communication device using an analog BF or a hybrid BF.

[0010] It is desirable to reduce the processing cost when performing calibration in wireless communication devices and the like. An object of the present disclosure is to provide an electronic device, a control method, and a program that can reduce the processing cost when performing calibration. According to one embodiment, it is possible to provide an electronic device, a control method, and a program that can reduce the processing cost when performing calibration.

[0011] First, the technical matters considered by the applicant when conceiving the present invention will be explained.

[0012] Known methods for achieving simultaneous transmission and reception (duplex communication) in wireless communication include, for example, Time Division Duplex (TDD) and Frequency Division Duplex (FDD). The TDD method achieves pseudo-simultaneous transmission and reception by reversing the communication direction every short time. The FDD method achieves simultaneous transmission and reception by dividing the frequency band of the communication path.

[0013] In TDD wireless communication devices, channel reciprocity is utilized. For example, in nonCodebook (NCB) type MIMO (Multi-Input Multi-Output) precoding in 5G (fifth generation mobile communication system), a precoding matrix is ​​generated using channel reciprocity. Here, channel reciprocity refers to, for example, a property in which a channel transmitted from wireless communication device A and received at wireless communication device B and a channel transmitted from wireless communication device B and received at wireless communication device A match in terms of transmission and reception directions only. In other words, channel reciprocity refers to a property in which two channel matrices match in a transpose relationship.

[0014] 1 is a diagram illustrating channel reciprocity between transmission and reception in a wireless communication device. ａｎｔ The antennas are divided into two groups, a transmitting group A and a receiving group B. In the example shown in FIG. 1, both the transmitting group A and the receiving group B have N ａｎｔ In the wireless communication device shown in FIG. ａｎｔ For convenience, the transmitting group A including two antennas is interpreted as wireless communication device A, and N ａｎｔ For convenience, the receiving group B including two antennas may be interpreted as the wireless communication device B.

[0015] In the wireless communication device shown in Fig. 1, channel reciprocity means that the channel from group A to group B and the channel from group B to group A are identical except for the fact that they are oriented differently (intra-array channels). Hereinafter, a matrix formed by the amount of fluctuation in amplitude and phase in the propagation path (channel) between each transmitting antenna and receiving antenna will be referred to as a channel matrix H. Also, the channel matrix of the channel from group A to group B will be referred to as H. Ａ→Ｂ and the channel matrix of the channel from group B to group A is H Ｂ→Ａ It is written as follows.

[0016] That is, in the wireless communication device shown in FIG. 1, channel reciprocity means that the channel (H Ａ→Ｂ ), and a channel from group B to group A (H Ｂ→Ａ ) can be expressed as a relationship obtained by transposing the channel matrix. When the transpose of the channel matrix is ​​represented by T, this relationship can be expressed as the following equation (1).

[0017] On the other hand, in a wireless communication device using the FDD system, different frequency bands are used for transmission and reception. Therefore, channel reciprocity does not hold in the FDD system. Therefore, in order for wireless communication device A to use a channel directed from wireless communication device A to wireless communication device B, it is necessary to feed back channel information estimated in wireless communication device B to wireless communication device A. In particular, in Massive MIMO, the number of antenna elements increases, and therefore the amount of channel information that needs to be fed back becomes an issue.

[0018] In contrast, in a TDD wireless communication device, the same frequency band is used for transmission and reception. Therefore, as described above, channel reciprocity holds in a TDD wireless communication device. Therefore, in order for wireless communication device A to use the channel directed from wireless communication device A to wireless communication device B, it is sufficient to use the channel information estimated by wireless communication device A using a known signal transmitted from wireless communication device B. Therefore, in a TDD wireless communication device, feedback of channel information is not required.

[0019] For the above reasons, Massive MIMO is well suited to the TDD system. However, in a real TDD system, transmitted and received signals pass through different circuits (e.g., a phase shifter, a power amplifier (PA), and / or a low noise amplifier (LNA)) within a wireless communication device. For this reason, channel reciprocity is lost in a real TDD wireless communication device. Therefore, in order to maintain channel reciprocity in a real TDD wireless communication device, it is desirable to perform some kind of correction, calibration, or the like.

[0020] Therefore, an electronic device according to an embodiment corrects the phase and / or amplitude of transmitting and receiving antenna elements so as to maintain channel reciprocity in a TDD system using analog band-fault filtering or hybrid band-fault filtering. The correction vector used for such correction is an eigenvalue vector obtained by calculating eigenvalues. Generally, the computational cost required for calculating eigenvalues ​​can be relatively high. However, an electronic device according to an embodiment can simplify the calculation of the correction value. Therefore, the electronic device according to an embodiment can calculate a correction vector with a relatively low computational cost compared to the computation of typical eigenvalues. Therefore, the electronic device according to an embodiment can reduce the processing load of a processing device such as a central processing unit (CPU) or a digital signal processor (DSP), thereby reducing power consumption. Furthermore, the electronic device according to an embodiment can be expected to reduce the specifications required for a processing device such as a CPU or a DSP.

[0021] Next, an electronic device according to an embodiment will be described with reference to Fig. 2, which is a diagram showing a schematic configuration of the electronic device according to an embodiment.

[0022] As shown in FIG. 2, the electronic device 1 according to the embodiment includes a 2N sub-panel such as a sub-panel 10A and a sub-panel 10B. Ｓ In FIG. 2, 2N sub-panels may be provided. ＳOf the sub-panels, only sub-panels 10A and 10B are shown in the figure, and the other sub-panels are not shown. An electronic device 1 according to an embodiment may be configured as, for example, a wireless communication device.

[0023] Also, as shown in FIG. 2, each sub-panel such as sub-panel 10A and sub-panel 10B has N Ａ Each sub-panel may include antenna elements. Fig. 2 illustrates only some of the antenna elements included in each sub-panel, and does not illustrate the other antenna elements. Also, in Fig. 2, the sub-panels and / or antenna elements are each shown schematically. The specific configuration and function of each sub-panel, such as sub-panel 10A and sub-panel 10B, will be described further below.

[0024] As shown in FIG. 2 , the electronic device 1 according to an embodiment may include a baseband unit 20. Furthermore, the baseband unit 20 of the electronic device 1 according to an embodiment may include a correction unit 30. Each sub-panel, such as the sub-panel 10A and the sub-panel 10B, is electrically connected to the baseband unit 20. The baseband unit 20 may have a configuration similar to or equivalent to that of a typical wireless communication device, except for the inclusion of the correction unit 30 according to an embodiment. Therefore, a detailed description of the baseband unit 20 will be omitted. The correction unit 30 may be implemented inside the baseband unit 20 or outside the baseband unit 20. Each sub-panel, such as the sub-panel 10A and the sub-panel 10B, may be electrically connected to the correction unit 30. The specific configuration and function of the correction unit 30 will be described further below.

[0025] The electronic device 1 according to an embodiment may not include some of the functional units shown in Fig. 2, or may include functional units other than those shown in Fig. 2. Furthermore, the system according to an embodiment may be configured to include the entire electronic device 1 or at least a part of the electronic device 1.

[0026] 3 is a diagram showing in more detail the functional configuration of a part of the electronic device 1 according to one embodiment. For ease of explanation, the configuration of the electronic device 1 shown in FIG. 3 is partially simplified from the configuration of the electronic device 1 shown in FIG. 2. Specifically, the electronic device 1 shown in FIG. 3 is a 2N Ｓ The number of sub-panels is set to 2 (N Ｓ = 1). That is, the electronic device 1 shown in FIG. 3 includes two sub-panels (sub-panel 10A and sub-panel 10B). N Ｓ Even if N is 2 or more, Ｓ By regarding the sub-panels as one sub-panel, calibration (correction) can be performed by the electronic device 1 according to the embodiment. Also, each of the sub-panels 10A and 10B shown in FIG. 2 includes four antenna elements (antenna elements 110) (N Ａ 3, the sub-panel 10A includes four antenna elements 110, and the sub-panel 10B also includes four antenna elements 110.

[0027] As described above, the electronic device 1 shown in FIG. 3 includes two sub-panels, sub-panel 10A and sub-panel 10B. Each of sub-panels 10A and 10B includes two antenna elements 110. Sub-panel 10A may include two antenna elements 110 and two RF (Radio Frequency) units 120 corresponding to the respective antenna elements 110. Each antenna element 110 may be electrically connected to its corresponding RF unit 120. As shown in FIG. 3, sub-panel 10A may also include an ADC / DAC 130. Each ADC / DAC 130 may be electrically connected to each of the RF units 120 in sub-panel 10A.

[0028] 3, the subpanel 10B may have the same configuration as the subpanel 10A. Furthermore, when the electronic device 1 according to the embodiment includes a subpanel other than the subpanels 10A and 10B, the other subpanel may have the same configuration as the subpanels 10A and 10B.

[0029] The electronic device 1 according to an embodiment may not include some of the functional units shown in FIG. 3, or may include functional units other than those shown in FIG.

[0030] For example, the electronic device 1 may include a control unit that controls each functional unit constituting the electronic device 1. In this case, the control unit may include at least one processor, such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), to provide control and processing capabilities for executing various functions. The control unit may be implemented as a single processor, several processors, or individual processors. The processor may be implemented as a single integrated circuit. An integrated circuit is also called an IC (Integrated Circuit). The processor may be implemented as multiple integrated circuits and discrete circuits connected to each other in a communicative manner. The processor may be implemented based on various other known technologies. Furthermore, the control unit may be configured to include at least one of software and hardware resources, for example. Furthermore, in one embodiment, the control unit may be configured by specific means in which software and hardware resources work together.

[0031] The control unit may be configured as, for example, a CPU or DSP and a program executed by the CPU or DSP. The program executed by the control unit and the results of the processing executed by the control unit may be stored in, for example, any memory. The control unit may include, as appropriate, a memory necessary for the operation of the control unit.

[0032] FIG. 4 is a diagram showing in more detail the functional configuration of one of the RF units 120 shown in FIG.

[0033] 4, the RF unit 120 may include a power amplifier (PA) 122, a low noise power amplifier (LNA) 124, a phase shifter 126, a switch 128A, and a switch 128B. The RF unit 120 according to one embodiment may not include some of the functional units shown in FIG. 4, or may include functional units other than those shown in FIG. 4.

[0034] The PA 122 amplifies the power of the transmission signal supplied from the phase shifter 126 based on information stored in, for example, an arbitrary memory, etc. The technology itself, such as an amplifier that amplifies the power of the transmission signal, is already known, so a detailed description thereof will be omitted.

[0035] The LNA 124 amplifies, with low noise, a received signal based on radio waves received by the antenna element 110, based on information stored in a memory, for example. The LNA 124 may be a low noise amplifier, and amplifies, with low noise, the received signal supplied from the antenna element 110. The technology itself for amplifying a received signal with low noise is already known, so a detailed description thereof will be omitted.

[0036] In this way, the PA 122 and the LNA 124 control the amplitude of the signal. Therefore, when performing calibration in the electronic device 1 according to an embodiment, the square of the amplitude component of the correction value may be set in the PA 122 and / or the LNA 124.

[0037] The phase shifter 126 controls the phase of the signal transmitted by the antenna element 110 and / or the signal received by the antenna element 110. Specifically, the phase shifter 126 may adjust the phase of the transmission signal or the reception signal by appropriately advancing or delaying the phase of the transmission signal or the reception signal based on information stored in a memory or the like. By the multiple phase shifters 126 appropriately adjusting the phase of each transmission signal or reception signal, the radio waves transmitted or received from the multiple antenna elements 110 constructively interact with each other in a predetermined direction to form a beam (beamforming).

[0038] The phase shifter 126 applies phase rotation to the analog signal. The precision of the phase rotation amount of the phase shifter is expressed by the number of bits. For example, in the case of 2 bits, the phase shifter can apply a rotation of {0, 90, 180, 360 degrees} to the signal.

[0039] In this way, the phase shifter 126 controls the phase of the signal. Therefore, when performing calibration in the electronic device 1 according to an embodiment, the phase component of the correction value may be set in the phase shifter 126.

[0040] The switches 128A and 128B are each capable of switching between a plurality of electrical connections.

[0041] 4 , the antenna element 110 and the RF unit 120 may be electrically connected. The antenna element 110 may be electrically connected to the PA 122 or the LNA 124 via a switch 128A. That is, by switching the switch 128A, the antenna element 110 is selectively connected to the PA 122 or the LNA 124.

[0042] The PA 122 may be electrically connected to the phase shifter 126. The LNA 124 may also be electrically connected to the phase shifter 126. As shown in FIG. 4, the PA 122 and the LNA 124 may be connected to their corresponding phase shifters 126. Also, as shown in FIG. 4, the phase shifter 126 connected to the PA 122 and the phase shifter 126 connected to the LNA 124 may be electrically connected to the ADC / DAC 130 ( FIG. 3 ) via a switch 128B. That is, by switching the switch 128B, the ADC / DAC 130 is selectively connected to the phase shifter 126 connected to the PA 122 or the phase shifter 126 connected to the LNA 124.

[0043] In the RF section 120, switching between the switch 128A and the switch 128B can switch between reception and transmission of the antenna element 110. As shown in Fig. 4, when transmitting radio waves from the antenna element 110, the signal is transmitted via the PA 122. On the other hand, when receiving radio waves from the antenna element 110, the signal is received via the LNA 124.

[0044] 3 , the RF units 120 included in each of the sub-panels 10A and 10B, two each, may be electrically connected to the corresponding ADC / DAC 130. Furthermore, the ADC / DAC 130 of the sub-panel 10A and the ADC / DAC 130 of the sub-panel 10B may each be electrically connected to the baseband unit 20. Furthermore, the ADC / DAC 130 of the sub-panel 10A and the ADC / DAC 130 of the sub-panel 10B may each be electrically connected to the correction unit 30.

[0045] The ADC / DAC 130 may have the functions of an ADC (Analog to Digital Converter) and a DAC (Digital to Analog Converter). That is, the ADC / DAC 130 can convert an analog signal into a digital signal and can also convert a digital signal into an analog signal. The ADC / DAC 130 may function as a DAC when transmitting radio waves from the antenna element 110, and may function as an ADC when receiving radio waves from the antenna element 110.

[0046] FIG. 5 is a diagram showing in more detail the functional configuration of the correction unit 30 shown in FIG.

[0047] 5, the correction unit 30 may include a multiplexer 310, a signal generation unit 320, a channel estimation unit 330, a channel matrix memory 340, a correction value calculation unit 350, and a correction value memory 360. The correction unit 30 according to one embodiment may not include some of the functional units shown in FIG. 5, or may include functional units other than those shown in FIG. 5.

[0048] At least some of the functional units included in the correction unit 30 may be configured with hardware and / or software. At least some of the functional units included in the correction unit 30 may include at least one processor, such as a CPU or DSP. In this case, at least some of the functional units included in the correction unit 30 may be implemented collectively by a single processor, by several processors, or by individual processors. The processor may be implemented as a single integrated circuit. An integrated circuit is also called an IC (Integrated Circuit). The processor may be implemented as multiple integrated circuits and discrete circuits connected to each other in a communicative manner. The processor may be implemented based on various other known technologies. Furthermore, at least some of the functional units included in the correction unit 30 may be configured to include at least one of software and hardware resources, for example. Furthermore, in one embodiment, at least some of the functional units included in the correction unit 30 may be configured by specific means in which software and hardware resources work together.

[0049] The multiplexer 310 has the function of outputting multiple inputs as a single signal. The multiplexer 310 has the function of combining multiple data streams into a single multiplexed stream. The multiplexer 310 may have the function of a regular multiplexer and the corresponding function of a demultiplexer. The multiplexer 310 can be configured to include a common multiplexer used in the field of communications technology, and therefore will not be described in further detail.

[0050] The multiplexer 310 may output the signal generated by the signal generation unit 320 to the sub-panel 10A and / or the sub-panel 10B. The multiplexer 310 may also output the signal input from the sub-panel 10A and / or the sub-panel 10B to the channel estimation unit 330.

[0051] The signal generating unit 320 may have a general signal generating function used in the field of communication technology. In the electronic device 1 according to one embodiment, the signal generating unit 320 may generate, for example, a known signal for channel estimation.

[0052] The channel estimation unit 330 has a function of estimating the channel matrix H. The channel estimation unit 330 may estimate the channel matrix H by switching between transmission and reception of sub-panels such as the sub-panel 10A and the sub-panel 10B shown in FIG. 3 . In this case, the channel estimation unit 330 may estimate the channel matrix H by using a known signal for channel estimation generated by the signal generation unit 320. For example, the channel estimation unit 330 may estimate the channel matrix H from the sub-panel 10A to the sub-panel 10B. Ａ→Ｂ and the channel matrix H from the sub-panel 10B to the sub-panel 10A. Ｂ→Ａ It may be estimated that

[0053] The channel estimation unit 330 may estimate the channel matrix H by using various methods. For example, the channel estimation unit 330 may perform channel estimation as follows. That is, the channel estimation unit 330 may repeatedly transmit and receive a known signal while sequentially setting column vectors of an orthogonal matrix (e.g., a Hadamard matrix or a DFT (discrete Fourier transform) matrix) in the phase shifters 126 of the transmitting and receiving sub-panels. Here, sequentially setting the column vectors of the orthogonal matrix in the phase shifters 126 may mean, for example, the following operation. That is, first, the first column vector of the orthogonal matrix is ​​set in the phase shifter 126, then the second column vector of the orthogonal matrix is ​​set in the phase shifter 126, and then the same operation is repeated for the third column vector and onward.

[0054] The channel matrix memory 340 may be a memory that stores or memorizes the channel matrix H estimated by the channel estimation unit 330. The channel matrix memory 340 may be configured, for example, by a semiconductor memory or the like, but is not limited to this and may be any storage device. The channel matrix memory 340 may be an internal memory of a CPU or DSP used as a controller.

[0055] The correction value calculation unit 350 calculates the two estimated channel matrices (H Ａ→Ｂ and HＢ→Ａ ) and calculates a correction value used when the electronic device 1 performs calibration. The calculation of this correction value will be described in more detail below.

[0056] The correction value memory 360 may be a memory that stores or memorizes the correction values ​​calculated by the correction value calculation unit 350. The correction value memory 360 may be configured, for example, by a semiconductor memory or the like, but is not limited to this and may be any storage device. The correction value memory 360 may also be an internal memory of the CPU or DSP used as a controller.

[0057] The electronic device 1 according to the embodiment can perform calibration using the correction values ​​stored in the correction value memory 360 .

[0058] Next, a further description will be given of the calculation of the correction value by the correction unit 30. Here, the correction value calculated by the correction unit 30 may be a correction value used when the electronic device 1 performs calibration.

[0059] (Step S1) The channel estimation unit 330 calculates a channel estimation matrix H Ａ→Ｂ and H Ｂ→Ａ Here, the channel estimation matrix may refer to the channel matrix estimated by the channel estimation unit 330. In this embodiment, as shown in FIG. 3 , the number of antenna elements 100 on each sub-panel is set to four, and therefore the channel estimation matrix is ​​a 4×4 matrix (a matrix with four rows and four columns). The channel estimation unit 330 may store the estimated channel matrix in the channel matrix memory 340.

[0060] (Step S2) Next, the correction value calculation unit 350 calculates H Ｔ Ａ→Ｂ (channel estimation matrix H Ａ→Ｂ Each element of the channel estimation matrix H Ｂ→Ａ The correction value calculation unit 350 may create the matrix D based on the channel estimation matrix stored in the channel matrix memory 340. The matrix D is obtained by dividing the channel matrix H estimated by the channel estimation unit 330.Ａ→Ｂ and H Ｂ→Ａ Hereinafter, the matrix D will also be referred to as the error matrix (error matrix D) where appropriate. Here, the elements of the matrix D are expressed as d ｉｊ (where i indicates the row number and j indicates the column number). ｉｊ is the product of the reciprocal of the error (i.e., the correction value) of the i-th receiving antenna of the sub-panel 10A and the reciprocal of the error (i.e., the correction value) of the j-th transmitting antenna of the sub-panel 10B. ｉｊ is a complex value.

[0061] (Step S3) Next, the correction value calculation unit 350 calculates individual correction values ​​for the receiving antennas of the sub-panel 10A. To this end, the correction value calculation unit 350 divides each component of the second row and beyond of the matrix D, using the first row as the reference (i.e., each component of the first row). Here, an example using the first row as the reference is described, but a row other than the first row may also be used as the reference. Ideally, as a result of the above division, each component of the same row should have the same value. However, in reality, due to factors such as thermal noise generated by each device, it is expected that the components of the same row will not have the same value as a result of the above division. Therefore, after performing the above division, the correction value calculation unit 350 calculates the average of each component of the same row and defines the result as shown in the following equation (2). In equation (2), i is the row number.

[0062] In the above formula (2), the average of each component in the same row is calculated after the above division, but the calculation is not limited to this. For example, the correction value calculation unit 350 may select the value that maximizes the absolute value of each component in the same row after the above division.

[0063] Hereinafter, the correction matrix for each receiving antenna of the sub-panel 10A is expressed as in the following equation (3).

[0064] The above formula (3) is defined as the following formula (4): In formula (4), diag means a diagonal matrix, which is a 4×4 matrix in this embodiment.

[0065] (Step S4) Next, the correction value calculation unit 350 calculates individual correction values ​​for the transmitting antennas of the sub-panel 10B. To this end, the correction value calculation unit 350 divides each component of the second and subsequent columns of matrix D, using the first column as a reference (i.e., each component of the first column). Here, columns based on the first column are described, but a column other than the first column may be used as a reference. Ideally, as a result of the above division, each component of the same column should have the same value. However, in reality, it is expected that the components of the same column will not have the same value as a result of the above division. Therefore, after performing the above division, the correction value calculation unit 350 calculates the average of each component of the same column and defines the result as shown in the following equation (5). In equation (5), i is the number of columns.

[0066] In the above formula (5), the average of each component in the same column is calculated after the above division, but the calculation is not limited to this. For example, the correction value calculation unit 350 may select the value that maximizes the absolute value of each component in the same column after the above division.

[0067] Hereinafter, the correction matrix for each transmitting antenna of the sub-panel 10B is expressed as in the following equation (6).

[0068] The above formula (6) is defined as the following formula (7): In formula (7), diag means a diagonal matrix, which is a 4×4 matrix in this embodiment.

[0069] (Step S5) Next, the correction value calculation unit 350 calculates the following equation (8). The calculation result of equation (8) is expressed as a matrix X. The matrix X is calculated by subtracting the channel estimation matrix H Ｂ→Ａ Hereinafter, the matrix X may be referred to as a first correction matrix (first correction matrix X) where appropriate.

[0070] (Step S6) Next, the correction value calculation unit 350 calculates H Ｔ Ａ→ＢEach component of x is divided by the corresponding component of matrix X to calculate the average value of the values. The average value calculated in this manner is denoted as γ. Here, the average value of each value is calculated after each of the above divisions, but the calculation is not limited to this. For example, the correction value calculation unit 350 may select the value with the largest absolute value among the values ​​after each of the above divisions.

[0071] In this way, the correction value calculation unit 350 generates a correction matrix common to all antennas as shown in the following equation (9). In equation (9), diag means a diagonal matrix, which is a 4 × 4 matrix in this embodiment. Hereinafter, matrix C will also be referred to as a second correction matrix (second correction matrix C) as appropriate.

[0072] (Step S7) Next, the correction value calculation unit 350 outputs the diagonal component values ​​of the calculation result shown in the following equation (10) as the receiving antenna correction values ​​of the sub-panel 10A. That is, the diagonal component values ​​of equation (10) may be used as the receiving antenna correction values ​​of the sub-panel 10A.

[0073] Furthermore, the correction value calculation unit 350 outputs the diagonal component values ​​of the matrix shown in the following equation (11) as the transmitting antenna correction values ​​of the sub-panel 10B. That is, the diagonal component values ​​of equation (11) may be used as the transmitting antenna correction values ​​of the sub-panel 10B.

[0074] Furthermore, the correction value calculation unit 350 may output the diagonal component values ​​of the matrix shown in the following equation (12) as the receiving antenna correction values ​​of the sub-panel 10A. That is, the diagonal component values ​​of equation (12) may be used as the receiving antenna correction values ​​of the sub-panel 10A.

[0075] Furthermore, the correction value calculation unit 350 may output the diagonal component values ​​of the calculation result shown in the following equation (13) as the transmitting antenna correction values ​​of the sub-panel 10B. That is, the diagonal component values ​​of equation (13) may be used as the transmitting antenna correction values ​​of the sub-panel 10B.

[0076] The correction value calculation unit 350 may store the correction value output (calculated) as described above in the correction value memory 360. This allows the electronic device 1 according to an embodiment to use the correction value stored in the correction value memory 360 when performing calibration.

[0077] As described above, the electronic device 1 according to an embodiment transmits and receives radio waves using a time division duplex (TDD) system. The electronic device 1 according to an embodiment may include a transmitter (e.g., sub-panel 10A) having at least one antenna (antenna element 110) and a receiver (e.g., sub-panel 10B) having at least one antenna (antenna element 110). The electronic device 1 may also include a channel estimation unit 330 and a correction value calculation unit 350. The channel estimation unit 330 estimates a first channel matrix, which is a channel matrix of a first channel, and a second channel matrix, which is a channel matrix of a second channel. Here, the first channel may be a channel extending from the transmitter (e.g., sub-panel 10A) to the receiver (e.g., sub-panel 10B). The second channel may be a channel extending from the receiver (e.g., sub-panel 10B) to the transmitter (e.g., sub-panel 10A). The correction value calculation section 350 calculates a correction value that establishes reciprocity between the first channel and the second channel based on the difference between the first channel matrix and the second channel matrix.

[0078] In one embodiment, the channel estimator 330 may estimate the first channel matrix and / or the second channel matrix using known signals for channel estimation generated by the signal generator 320. The channel estimator 330 may also estimate the first channel matrix and / or the second channel matrix by sequentially setting column vectors of an orthogonal matrix to the phase shifters 126 of the transmitter (e.g., sub-panel 10A) and the receiver (e.g., sub-panel 10B). In this case, the orthogonal matrix set in the phase shifters 126 may be a Hadamard matrix or a discrete Fourier transform (DFT) matrix.

[0079] In one embodiment, the correction value calculation section 350 may calculate a correction value for each antenna of the transmitting section (for example, the sub-panel 10A) and a correction value for each antenna of the receiving section (for example, the sub-panel 10B).

[0080] In one embodiment, the correction value calculation unit 350 may calculate a correction matrix for each antenna of the receiving unit (e.g., sub-panel 10B). In this case, the correction value calculation unit 350 may use an arbitrary row of an error matrix D, which is formed by dividing each element of a matrix obtained by transposing the first channel matrix by the corresponding element of the second channel matrix, as a reference, and calculate the correction matrix based on values ​​obtained by dividing each element of the other rows of the error matrix D. In this case, the correction value calculation unit 350 may also use an arbitrary row of the error matrix D as a reference and calculate the correction matrix for each antenna of the receiving unit (e.g., sub-panel 10B) based on an average value of values ​​obtained by dividing each element of the other rows of the error matrix D.

[0081] In one embodiment, the correction value calculation unit 350 may calculate a correction matrix for each antenna of the transmitter (e.g., sub-panel 10A). In this case, the correction value calculation unit 350 may use an arbitrary column of an error matrix D, which is formed by dividing each element of a matrix obtained by transposing the first channel matrix by the corresponding element of the second channel matrix, as a reference, and calculate the correction matrix based on values ​​obtained by dividing each element of the other columns of the error matrix D. In this case, the correction value calculation unit 350 may use an arbitrary column of the error matrix D as a reference and calculate the correction matrix for each antenna of the transmitter (e.g., sub-panel 10A) based on an average value of values ​​obtained by dividing each element of the other columns of the error matrix D.

[0082] In one embodiment, the correction value calculation unit 350 may calculate the first correction matrix X based on a correction matrix for each antenna of the transmitter (e.g., sub-panel 10A), a second channel matrix, and a correction matrix for each antenna of the receiver (e.g., sub-panel 10B). In this case, the correction value calculation unit 350 may calculate the second correction matrix C based on components obtained by dividing each component of a matrix obtained by transposing the first channel matrix by the corresponding component of the first correction matrix X. In this case, the correction value calculation unit 350 may also calculate the second correction matrix C based on the average value of values ​​obtained by dividing each component of a matrix obtained by transposing the first channel matrix by the corresponding component of the first correction matrix X.

[0083] In one embodiment, the correction value calculation unit 350 may calculate a correction value for the antenna of the transmitting unit (e.g., sub-panel 10A) based on the second correction matrix C and the correction matrix for each antenna of the transmitting unit (e.g., sub-panel 10A). In this case, the correction value calculation unit 350 may calculate a correction value for the antenna of the receiving unit (e.g., sub-panel 10B) based on the correction matrix for each antenna of the receiving unit (e.g., sub-panel 10B).

[0084] In one embodiment, the correction value calculation unit 350 may calculate the correction value of the antenna of the transmitting unit (e.g., sub-panel 10A) based on a correction matrix for each antenna of the transmitting unit (e.g., sub-panel 10A). In this case, the correction value calculation unit 350 may calculate the correction value of the antenna of the receiving unit (e.g., sub-panel 10B) based on the second correction matrix C and the correction matrix for each antenna of the receiving unit (e.g., sub-panel 10B).

[0085] Furthermore, the electronic device 1 according to an embodiment may implement analog beamforming or hybrid beamforming.

[0086] As described above, the electronic device 1 according to an embodiment may include two or more sub-panels each including one or more antenna elements 110, and may perform TDD wireless communication. The electronic device 1 according to an embodiment corrects the phase and / or amplitude of the transmitting and receiving antenna elements to establish channel reciprocity. The electronic device 1 according to an embodiment divides the multiple antenna elements 110 into two groups, transmits and receives signals from each group, estimates one of the two channel matrices, transposes the transposed matrices, and divides the transposed matrices by the corresponding elements of the other channel matrix. In this manner, the electronic device 1 according to an embodiment can calculate a correction value for calibration by calculating errors for each of the transmitting and receiving antenna elements 110 and averaging them. As a result, the electronic device 1 according to an embodiment can correct channel reciprocity in a wireless communication device using analog beamforming or hybrid beamforming.

[0087] As described above, the computational cost required to calculate eigenvalues ​​when determining a correction vector used for such correction can generally be relatively high. However, according to an electronic device of an embodiment, the calculation of the correction value can be simplified by performing simple arithmetic operations. Therefore, according to an electronic device of an embodiment, the computational cost required to calculate a correction vector can be kept relatively low compared to the calculation of a typical eigenvalue. Therefore, according to an electronic device of an embodiment, the processing load of a processing device such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor) can be reduced, thereby reducing power consumption. Furthermore, according to an electronic device of an embodiment, it is expected that the specifications required for a processing device such as a CPU or a DSP can be kept relatively low.

[0088] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present disclosure. For example, functions included in each component or step can be rearranged so as not to cause logical inconsistencies, and multiple components or steps can be combined or divided into one. Although the embodiments of the present disclosure have been described primarily in terms of an apparatus, the embodiments of the present disclosure can also be realized as a method including steps executed by each component of the apparatus. The embodiments of the present disclosure can also be realized as a method, a program executed by a processor included in an electronic device, or a storage medium or recording medium on which a program is recorded. It should be understood that these are also encompassed within the scope of the present disclosure.

[0089] The above-described embodiments are not limited to implementation as the electronic device 1. For example, the above-described embodiments may be implemented as a system including the electronic device 1. Furthermore, the above-described embodiments may be implemented as, for example, a control method for the electronic device 1 or a control method for a device such as a system including the electronic device 1. Furthermore, the above-described embodiments may be implemented as, for example, a program executed by a device such as the electronic device 1 or a system including the electronic device 1, or an information processing device (e.g., a computer). Furthermore, in the technology disclosed herein, all of the components of the electronic device 1 and / or a system including the electronic device 1 do not need to reside in a single housing. For example, the controllers and / or memory units of the components of the electronic device 1 and / or a system including the electronic device 1 may be connected to each other via a network that is wired, wireless, or a combination thereof.

[0090] REFERENCE SIGNS LIST 1 Electronic device 10A, 10B Sub-panel 20 Baseband section 30 Correction section 110 Antenna element 120 RF section 122 PA 124 LNA 126 Phase shifter 128A, 128B Switch 130 ADC / DAC 310 Multiplexer 320 Signal generation section 330 Channel estimation section 340 Channel matrix memory 350 Correction value calculation section 360 Correction value memory

Claims

1. An electronic device that transmits and receives radio waves using a time division duplex method, comprising: a transmitting unit with at least one antenna; a receiving unit with at least one antenna; a channel estimating unit that estimates a first channel matrix that is the channel matrix of a first channel oriented from the transmitting unit to the receiving unit, and a second channel matrix that is the channel matrix of a second channel oriented from the receiving unit to the transmitting unit; and a correction value calculating unit that calculates a correction value that establishes reciprocity between the first channel and the second channel based on the difference between the first channel matrix and the second channel matrix.

2. The electronic device according to claim 1, wherein the correction value calculation unit calculates a correction value for each antenna of the transmission unit and a correction value for each antenna of the reception unit.

3. The electronic device described in claim 1, wherein the correction value calculation unit calculates a correction matrix for each antenna of the receiving unit based on values ​​obtained by dividing an arbitrary row of an error matrix formed by dividing each element of a matrix obtained by transposing the first channel matrix by the corresponding element of the second channel matrix, by each element of other rows of the error matrix.

4. The electronic device according to claim 3, wherein the correction value calculation unit calculates a correction matrix for each antenna of the receiving unit based on the average value of each value obtained by dividing each component of an arbitrary row of the error matrix by the other rows of the error matrix.

5. The electronic device described in claim 1, wherein the correction value calculation unit calculates a correction matrix for each antenna of the transmitting unit based on values ​​obtained by dividing an arbitrary column of an error matrix formed by dividing each element of a matrix obtained by transposing the first channel matrix by the corresponding element of the second channel matrix, by each element of other columns of the error matrix.

6. The electronic device according to claim 5, wherein the correction value calculation unit calculates a correction matrix for each antenna of the transmitting unit based on the average value of each value obtained by dividing an arbitrary column of the error matrix by each component of the other columns of the error matrix.

7. The electronic device according to claim 1, wherein the correction value calculation unit calculates a first correction matrix based on a correction matrix for each antenna of the transmitting unit, the second channel matrix, and a correction matrix for each antenna of the receiving unit.

8. The electronic device according to claim 7, wherein the correction value calculation unit calculates a second correction matrix based on components obtained by dividing each component of a matrix obtained by transposing the first channel matrix by the corresponding component of the first correction matrix.

9. The electronic device according to claim 8, wherein the correction value calculation unit calculates the second correction matrix based on an average value of values ​​obtained by dividing each element of a matrix obtained by transposing the first channel matrix by each corresponding element of the first correction matrix.

10. The electronic device described in claim 8, wherein the correction value calculation unit calculates a correction value for the antenna of the transmitting unit based on the second correction matrix and a correction matrix for each antenna of the transmitting unit, and calculates a correction value for the antenna of the receiving unit based on a correction matrix for each antenna of the receiving unit.

11. The electronic device described in claim 8, wherein the correction value calculation unit calculates a correction value for the antenna of the transmitting unit based on a correction matrix for each antenna of the transmitting unit, and calculates a correction value for the antenna of the receiving unit based on the second correction matrix and a correction matrix for each antenna of the receiving unit.

12. The electronic device according to claim 1, wherein the channel estimator estimates the first channel matrix and / or the second channel matrix using a known signal for channel estimation.

13. The electronic device of claim 1, wherein the channel estimation unit estimates the first channel matrix and / or the second channel matrix by sequentially setting column vectors of an orthogonal matrix in phase shifters of the transmission unit and the reception unit.

14. The electronic device according to claim 3, wherein the orthogonal matrix is ​​a Hadamard matrix or a discrete Fourier transform matrix.

15. A control method for electronic equipment that transmits and receives radio waves using a time division duplex system, the electronic equipment having a transmitting unit with at least one antenna and a receiving unit with at least one antenna, the control method including: a channel estimation step of estimating a first channel matrix that is a channel matrix of a first channel directed from the transmitting unit to the receiving unit and a second channel matrix that is a channel matrix of a second channel directed from the receiving unit to the transmitting unit; and a correction value calculation step of calculating a correction value that establishes reciprocity between the first channel and the second channel based on the difference between the first channel matrix and the second channel matrix.

16. A program to be executed by an electronic device that transmits and receives radio waves using a time division duplex method, the electronic device having a transmitting unit with at least one antenna and a receiving unit with at least one antenna, the program causing the electronic device to execute the following steps: a channel estimation step of estimating a first channel matrix that is a channel matrix of a first channel directed from the transmitting unit to the receiving unit, and a second channel matrix that is a channel matrix of a second channel directed from the receiving unit to the transmitting unit; and a correction value calculation step of calculating a correction value that establishes reciprocity between the first channel and the second channel based on the difference between the first channel matrix and the second channel matrix.

Images