Transmitting device, receiving device, transmitting method, receiving method, and program

Abstract

To achieve high-performance beamforming.SOLUTION: A transmission method to be performed by a transmitter includes: generating a digital calibration signal; performing transmission processing including digital-to-analog conversion on second digital signals obtained by adding the digital calibration signal to first digital signals corresponding to antenna elements of the transmitter, respectively, to generate first analog signals; performing receiving processing including analog-to-digital conversion on the first analog signals passing through each of the antenna elements, to generate third digital signals corresponding to the antenna elements, respectively; performing correlation calculation between the digital calibration signal and the third digital signals to calculate transmission delay characteristics corresponding to the antenna elements, respectively; calculating transmission delay characteristic correction amounts for each of the antenna elements based on the transmission delay characteristics; and correcting the transmission delay characteristics based on the transmission delay characteristic correction amounts.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a transmitting device, a receiving device, a transmitting method, a receiving method, and a program, and more particularly to a transmitting device, a receiving device, a transmitting method, a receiving method, and a program for performing beamforming in wireless transmission. [Background technology]

[0002] One of the key technologies for 5G (5th Generation) mobile communication systems is 5G multi-antenna technology (for example, Non-Patent Document 1). 5G multi-antenna technology compensates for propagation loss in high frequency bands by using beamforming, which adaptively controls antenna directivity using a massively multi-element antenna. Beamforming can be broadly divided into the following three types (for example, Chapter 3.3 of Non-Patent Document 1). (1) Fully digital beamforming (2) Full analog beamforming (3) Hybrid beamforming

[0003] (1) Full digital beamforming has excellent performance due to digital precoding processing, but requires the same number of digital-to-analog converters (DACs) and up-converters (UCs) as the number of antenna elements, which makes it expensive in high frequency bands and results in relatively high power consumption.

[0004] (2) Full analog beamforming eliminates the need for digital precoding processing and has the simplest circuit configuration, but it requires reducing the number of beams and generating narrow beams to maintain orthogonality between beams.

[0005] (3) Hybrid beamforming uses a mixture of digital and analog to perform beamforming, so its performance and circuit complexity are intermediate between (1) full digital beamforming and (2) full analog beamforming.

[0006] Meanwhile, progress is being made internationally in environmental improvements and technological development toward the commercialization of High-Altitude Platform Stations (HAPS), and their widespread adoption is expected. In particular, expectations are rising for fixed communication systems using HAPS to ensure redundant routes for backhaul lines via the sky. High-speed, high-capacity HAPS systems are expected to be realized in conjunction with 5G networks using the 38 GHz band allocated to HAPS at WRC-19 (World Radiocommunication Conference 2019) (see, for example, Non-Patent Document 2). HAPS orbits in the stratosphere at an altitude of around 20 km, and uses beamforming to track signals between the HAPS and ground stations. HAPS requires the use of massively multiple-element antennas to compensate for propagation loss in high-frequency bands.

[0007] In all of the beamforming methods (1) to (3) above, inter-element calibration is important when controlling the phase (delay) of each antenna element because there are variations in the analog circuit characteristics between elements. In particular, the stratosphere at an altitude of around 20 km where HAPS resides is a harsh environment with extremely low temperatures of -70°C and pressure of 1 / 10 atmospheric pressure, so real-time and high-speed inter-element calibration is required.

[0008] In Patent Document 1, a pseudo-random sequence is added to a main signal, which is then sent from an array antenna and received by a receiving array antenna. The correlation between the received signal and the pseudo-random sequence, which is the same as that on the transmitting side, is calculated to calculate the phase characteristics for each antenna element, and inter-element phase calibration is performed. This enables real-time phase calibration without stopping the main signal.

[0009] On the other hand, when using a wideband signal as in Non-Patent Document 2, delay variations between elements tend to cause in-band phase tilt, adversely affecting beamforming performance. Therefore, to maintain beamforming performance, it is necessary to perform inter-element calibration to delay variations of less than one sample. In Patent Document 2, in order to suppress the settable range of the delay correction amount for each element, a calibration signal is sequentially injected into the transmit and receive circuits of each element, and the delay correction amount for each element is calculated using the delay measurement results of the transmit and receive circuits of each element obtained by correlation with the calibration signal. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Special Publication No. 2010-540894 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-213217 [Non-patent literature]

[0011] [Non-Patent Document 1] Suyama et al., "5G Multi-Antenna Technology," NTT DOCOMO Technical Journal, Vol. 23 No. 4, pp. 30-39 (January 2016) [Non-patent document 2] Suzuki et al., "Development of a 38GHz band wireless communication system linked to a 5G network using a high altitude platform (HAPS) - Study on high-speed, high-capacity backhaul lines for 5G networks," 2021 Institute of Electronics, Information and Communication Engineers General Conference, B-3-1 (March 2021) [Non-patent document 3] Ouchi et al., "Development of a 38GHz band wireless communication system linked to a 5G network using a high altitude platform (HAPS) - Study on full digital beamforming in a base station-mounted HAPS," 2021 Institute of Electronics, Information and Communication Engineers Society Conference, B-3-11 (September 2021) Summary of the Invention [Problem to be solved by the invention]

[0012] As mentioned above, fixed communication systems using HAPS are expected to realize high-speed, high-capacity transmission in the 38 GHz band. However, when using the 38 GHz band, which has significant rain attenuation, a massively multi-element antenna is originally expected to be used to compensate for propagation loss in high-frequency bands. Furthermore, the number of elements must be further increased to ensure sufficient rain attenuation margin. This increases the time required for calibration in proportion to the number of elements. In Patent Document 2, delay measurement by correlation is performed after the transmit and receive calibration signals pass through delay elements that correct delays in the receive and transmit circuits of the main signal, respectively. Therefore, the delay correction amount for each element must be calculated using the delay measurement results of the transmit and receive circuits of each element. This increases the time required for delay calibration between elements in proportion to twice the number of elements.

[0013] Non-limiting examples of the present disclosure contribute to providing a transmitting device, a receiving device, a transmitting method, and a receiving method that can achieve high-performance beamforming. [Means for solving the problem]

[0014] a transmission processing execution unit that performs transmission processing including digital-to-analog conversion on a second digital signal obtained by adding the digital calibration signal to a first digital signal corresponding to each of the plurality of antenna elements, thereby generating a first analog signal; a reception processing execution unit that performs reception processing including analog-to-digital conversion on the first analog signal that has passed through each of the plurality of antenna elements, thereby generating a third digital signal corresponding to each of the plurality of antenna elements; a transmission characteristic calculation unit that performs a correlation operation between the digital calibration signal and the third digital signal to calculate a transmission characteristic related to delay for each of the plurality of antenna elements, and calculates a transmission characteristic correction amount related to delay for each of the plurality of antenna elements based on the transmission characteristic related to delay; and a transmission characteristic correction unit that corrects the transmission characteristic related to delay based on the transmission characteristic correction amount.

[0015] a receiving device according to an embodiment of the present disclosure, the receiving device including a plurality of antenna elements; a calibration signal generating unit that generates a digital calibration signal; a transmission processing executing unit that performs transmission processing including digital-to-analog conversion on the digital calibration signal to generate a first analog signal; a reception processing executing unit that performs reception processing including analog-to-digital conversion on a third analog signal obtained by adding the first analog signal to a second analog signal received via each of the plurality of antenna elements to generate a first digital signal corresponding to each of the plurality of antenna elements; a reception characteristic calculating unit that performs a correlation operation between the digital calibration signal and the first digital signal to calculate a reception characteristic related to delay for each of the plurality of antenna elements and calculates a reception characteristic correction amount related to delay for each of the plurality of antenna elements based on the reception characteristic related to delay; and a reception characteristic correcting unit that corrects the reception characteristic related to delay based on the reception characteristic correction amount.

[0016] A transmission method according to one embodiment of the present disclosure includes a transmitting device generating a digital calibration signal, performing transmission processing including digital-to-analog conversion on a second digital signal obtained by adding the digital calibration signal to a first digital signal corresponding to each of a plurality of antenna elements included in the transmitting device, thereby generating a first analog signal, and performing reception processing including analog-to-digital conversion on the first analog signal that has passed through each of the plurality of antenna elements, thereby generating a third digital signal corresponding to each of the plurality of antenna elements, performing a correlation operation between the digital calibration signal and the third digital signal, calculating a transmission characteristic related to delay for each of the plurality of antenna elements, calculating a transmission characteristic correction amount related to delay for each of the plurality of antenna elements based on the transmission characteristic related to delay, and correcting the transmission characteristic related to delay based on the transmission characteristic correction amount.

[0017] A receiving method according to one embodiment of the present disclosure includes a receiving device generating a digital calibration signal, performing transmission processing including digital-to-analog conversion on the digital calibration signal to generate a first analog signal, performing reception processing including analog-to-digital conversion on a third analog signal obtained by adding the first analog signal to a second analog signal received via each of a plurality of antenna elements included in the receiving device, thereby generating a first digital signal corresponding to each of the plurality of antenna elements, performing a correlation operation between the digital calibration signal and the first digital signal to calculate a reception characteristic related to delay for each of the plurality of antenna elements, calculating a reception characteristic correction amount related to delay for each of the plurality of antenna elements based on the reception characteristic related to delay, and correcting the reception characteristic related to delay based on the reception characteristic correction amount.

[0018] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0019] According to one embodiment of the present disclosure, after a transmission calibration signal (or a reception calibration signal) passes through a reception processing execution unit (or a transmission processing execution unit) dedicated to the calibration signal, delay calibration can be performed by a single, transmission-only (or reception-only) correlation, thereby realizing high-performance beamforming.

[0020] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0021] [Figure 1]FIG. 1 illustrates an example of a configuration of a communication device according to a first embodiment of the present disclosure. [Figure 2] FIG. 1 illustrates an example of the configuration of a transmission characteristic calculation analog unit according to a first embodiment of the present disclosure. [Figure 3] FIG. 1 is a diagram illustrating an example of the configuration of a transmission / reception characteristic calculation unit according to a first embodiment of the present disclosure. [Figure 4] FIG. 10 shows an example of the results obtained by simulation of the change in peak correlation value due to delay and the change in EL correlation value due to delay. [Figure 5] FIG. 1 is a diagram illustrating an example of the configuration of a reception characteristic calculation analog unit according to a first embodiment of the present disclosure. [Figure 6] FIG. 10 is a flowchart showing an example of delay calibration between antenna elements (systems) in transmission or reception according to the second embodiment of the present disclosure. [Figure 7] FIG. 13 is a diagram showing another example of a flowchart for delay calibration between antenna elements (systems) in transmission or reception according to the third embodiment of the present disclosure. [Figure 8] FIG. 10 is a diagram illustrating an example of the configuration of a communication device according to a fourth embodiment of the present disclosure. [Figure 9] FIG. 13 is a diagram illustrating an example of the configuration of a transmission / reception characteristic calculation unit according to a fourth embodiment of the present disclosure. [Figure 10] FIG. 13 is a flowchart showing an example of delay calibration between antenna elements (systems) in transmission or reception according to the fifth embodiment of the present disclosure. [Figure 11] FIG. 20 is a diagram showing another example of a flowchart for delay calibration between antenna elements (systems) in transmission or reception according to the sixth embodiment of the present disclosure. [Figure 12] FIG. 20 is a flowchart showing another example of delay calibration between antenna elements (systems) in transmission or reception according to the seventh embodiment of the present invention. [Figure 13] FIG. 20 is a diagram showing another example of a flowchart for delay calibration between antenna elements (systems) in transmission or reception according to the eighth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0023] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0024] (Embodiment 1) 1 is a diagram illustrating an example of a configuration of a communication device 100 according to a first embodiment of the present disclosure. The communication device 100 includes M transmission signal generation units 110-1 to 110-M, a transmission digital precoding unit 115, N transmission characteristic correction units 175-1 to 175-N, a calibration signal generation unit 120, N DACs 125-1 to 125-N, N UCs 130-1 to 130-N, N power amplification units 135-1 to 135-N, N duplexers 140-1 to 140-N, and N antennas. The communication device 100 includes: N elements 145-1 to 145-N, a transmission characteristic calculation analog unit 180, a reception characteristic calculation analog unit 185, a transmission and reception characteristic calculation unit 190, N adders 195-1 to 195-N, L reception signal regeneration units 210-1 to 210-L, a reception digital precoding unit 215, N reception characteristic correction units 275-1 to 275-N, N analog to digital converters (ADCs) 225-1 to 225-N, N down converters (DCs) 230-1 to 230-N, and N power amplification units 235-1 to 235-N. Note that the components of the communication device 100 that perform digital processing may be implemented as an integrated circuit 105. Components that perform digital processing include, for example, transmission signal generation units 110-1 to 110-M, transmission digital precoding unit 115, calibration signal generation unit 120, DACs 125-1 to 125-N, reception signal regeneration units 210-1 to 210-L, reception digital precoding unit 215, ADCs 225-1 to 225-N, transmission characteristic correction units 175-1 to 175-N, transmission and reception characteristic calculation unit 190, and reception characteristic correction units 275-1 to 275-N. Note that integrated circuit 105 may include not only components that perform digital processing, but also some or all of the components that perform analog processing.

[0025] The transmitting side of the operation of the communication device 100 in FIG. 1 will be described below.

[0026] The transmission signal generation units 110-1 to 110-M generate transmission streams 1 to M and output them to the transmission digital precoding unit 115, respectively.

[0027] The transmission digital precoding unit 115 performs digital precoding for beamforming on M inputs (transmission streams 1 to M), generates N digital signals (main signals) corresponding to the N antenna elements, and outputs them to the corresponding transmission characteristic correction units 175-1 to 175-N.

[0028] The transmission characteristic correction units 175-1 to 175-N store the transmission characteristic (delay) correction amount indicated by the transmission characteristic correction amount signal input from the transmission and reception characteristic calculation unit 190 in a storage unit (not shown). Alternatively, the transmission characteristic (delay) correction amount may be stored in a storage unit (not shown) by the transmission and reception characteristic calculation unit 190. The transmission characteristic correction units 175-1 to 175-N perform inter-antenna element calibration by respectively correcting the characteristics of the digital signal (main signal) input from the transmission digital precoding unit 115 based on the transmission characteristic (delay) correction amount indicated by the transmission characteristic correction amount signal. Then, the transmission characteristic correction units 175-1 to 175-N output the calibrated digital signal to the DACs 125-1 to 125-N. Note that when pre-processing for performing inter-antenna element calibration is performed, the N digital signals (main signals) pass through the transmission characteristic correction units 175-1 to 175-N without being processed by the transmission characteristic correction units 175-1 to 175-N. Unless otherwise specified, the following describes a case where pre-processing is performed for performing calibration between antenna elements (that is, correction by transmission characteristic correction units 175-1 to 175-N).

[0029] The calibration signal generating unit 120 generates a calibration signal at a low power level and outputs it to the DACs 125-1 to 125-N. Although not shown, the calibration signal generating unit 120 also outputs the calibration signal to the transmission and reception characteristic calculating unit 190. An example of the calibration signal is a pseudo-random sequence such as an M sequence or a Gold sequence in which 0s and 1s are generated with approximately equal probability.

[0030] DACs 125-1 to 125-N each add the calibration signal input from calibration signal generator 120 to the main signal input from transmission characteristic correctors 175-1 to 175-N, then convert the digital signal into an analog signal and output it to UCs 130-1 to 130-N.

[0031] The UCs 130-1 to 130-N up-convert the analog signals input from the DACs 125-1 to 125-N to the transmission frequency band and output the signals to the power amplifiers 135-1 to 135-N, respectively.

[0032] The power amplifiers 135-1 to 135-N respectively amplify and output the power of the up-converted analog signals input from the power amplifiers 135-1 to 135-N. The analog signals output from the power amplifiers 135-1 to 135-N pass through duplexers 140-1 to 140-N and adders 195-1 to 195-N respectively, and are input to N antenna elements 145-1 to 145-N as transmission signals. The transmission signals input to the N antenna elements 145-1 to 145-N (i.e., the transmission signals that have passed through the N antenna elements 145-1 to 145-N) are then input to the transmission characteristic calculation analog unit 180 for processing by the transmission characteristic calculation analog unit 180, which will be described later.

[0033] The DACs 125-1 to 125-N, UCs 130-1 to 130-N, and power amplifiers 135-1 to 135-N perform transmission processing, including at least DA conversion, on the digital signals obtained by adding the calibration signals to the main signals, to generate analog signals.

[0034] The main signal is an example of a first digital signal in the transmission device and transmission method according to the present disclosure, the digital signal obtained by adding a calibration signal to the main signal is an example of a second digital signal in the transmission device and transmission method according to the present disclosure, and the analog signal generated after execution of the transmission process is an example of a first analog signal in the transmission device and transmission method according to the present disclosure.Furthermore, at least DACs 125-1 to 125-N (and possibly UCs 130-1 to 130-N and power amplifiers 135-1 to 135-N) are an example of a transmission process execution unit in the transmission device and transmission method according to the present disclosure.

[0035] The transmission characteristic calculation analog unit 180 performs reception processing such as down-conversion and AD conversion on the analog transmission signals input from the N antenna elements 145-1 to 145-N, and outputs the digital signals after the reception processing to the transmission and reception characteristic calculation unit 190. Note that in the communication device 100, when the transmission frequency and the reception frequency are different, only the signal on the transmission side is output from the transmission characteristic calculation analog unit 180 and input to the transmission and reception characteristic calculation unit 190.

[0036] The transmission and reception characteristic calculation unit 190 calculates the transmission characteristic using the digital signal input from the transmission characteristic calculation analog unit 180 .

[0037] As described above, delay measurement by correlation is performed after the transmission calibration signal passes through a receiver circuit dedicated to calibration signals (transmission characteristic calculation analog unit 180). That is, unlike Patent Document 2, delay measurement by correlation is performed without the transmission calibration signal passing through a delay element in the receiver circuit of the main signal.

[0038] 2 is a diagram showing an example of the configuration of the transmission characteristic calculation analog unit 180. The transmission characteristic calculation analog unit 180 includes an ADC 425, a DC 430, a power amplifier 435, and an input selection switch 437.

[0039] Input selection switch 437 sequentially selects one of N antenna elements 145-1 to 145-N, receives the analog signal from the selected antenna element, and outputs it to power amplification section 435.

[0040] The power amplifier 435 amplifies the power of the analog signal input from the input selection switch 437 and outputs it to the DC 430 .

[0041] The DC 430, like the DCs 230-1 to 230-N, down-converts the analog signal input from the power amplifier 435 from the reception frequency band and outputs the down-converted signal to the ADC 425.

[0042] The ADC 425 converts the analog signal input from the DC 430 into a digital signal and outputs it to the transmission / reception characteristic calculation unit 190 .

[0043] The DC 430, the ADC 425, the input selection switch 437, and the power amplifier 435 perform reception processing including at least AD conversion on the analog signals input via the N antenna elements 145-1 to 145-N, and generate a digital signal including a calibration signal (pseudo-random sequence).

[0044] The above digital signal is an example of a third digital signal in the transmission device and transmission method according to the present disclosure. At least the DC 430 (and possibly the ADC 425, input selection switch 437, and power amplifier 435, i.e., the transmission characteristic calculation analog unit 180) is an example of a reception processing execution unit or a first reception processing execution unit in the transmission device and transmission method according to the present disclosure.

[0045] A detailed description will be omitted for the case where pre-processing for performing inter-antenna element calibration has already been performed, i.e., the case where N digital signals (main signals) from transmission digital precoding unit 115 are processed and transmitted by transmission characteristic correction units 175-1 to 175-N. In this case, for transmission by N antenna elements 145-1 to 145-N, the digital signals that have undergone transmission characteristic correction corresponding to N antenna elements 145-1 to 145-N are finally input to N antenna elements 145-1 to 145-N via the above-mentioned DACs 125-1 to 125-N, UCs 130-1 to 130-N, power amplification units 135-1 to 135-N, and duplexers 140-1 to 140-N, respectively.

[0046] The digital signal that has undergone the transmission characteristic correction is an example of a second digital signal in the receiving device and receiving method according to the present disclosure. Also, at least DACs 125-1 to 125-N (and possibly UCs 130-1 to 130-N and power amplifiers 135-1 to 135-N) are an example of a second transmission processing execution unit in the receiving device and receiving method according to the present disclosure.

[0047] 3 is a diagram showing an example of the configuration of the transmission and reception characteristics calculation unit 190. The transmission and reception characteristics calculation unit 190 includes an input selection switch 441, correlation calculation units 343 and 443, EL (Early-Late) detection units 347 and 447, a transmission characteristics comparison unit 353, and a reception characteristics comparison unit 453.

[0048] The correlation calculation unit 343 performs a correlation calculation between the digital signal converted from the analog signal that has passed through the antenna elements 145-1 to 145-N by the transmission characteristic calculation analog unit 180 and input from the transmission characteristic calculation analog unit 180, and the calibration signal (pseudo-random sequence) generated by the calibration signal generation unit 120 and input from the calibration signal generation unit 120.

[0049] The EL detection unit 347 detects the peak value within one period of the pseudo-random sequence and obtains the desired correlation gain by performing correlation calculations over multiple periods as necessary. The EL detection unit 347 also outputs the EL correlation value, which is the result of subtracting the correlation value one sample after the peak value from the correlation value one sample before the peak value, to the transmission characteristic comparison unit 353 as the transmission characteristic.

[0050] The output from transmission characteristic calculation analog unit 180 is switched sequentially to each of N antenna elements 145-1 to 145-N, and transmission characteristic comparison unit 353 compares the characteristics of each of N antenna elements 145-1 to 145-N input from EL detection unit 347. Then, transmission characteristic comparison unit 353 calculates (or determines) a transmission characteristic correction amount for each of N antenna elements 145-1 to 145-N so that all characteristics are the same, generates a transmission characteristic correction amount signal indicating the transmission characteristic correction amount, and outputs it to transmission characteristic correction units 175-1 to 175-N.

[0051] The transmission and reception characteristic calculation unit 190 is an example of a transmission characteristic calculation unit in the transmission device and transmission method according to the present disclosure.

[0052] 4(a) and 4(b) are diagrams showing examples of the results obtained by simulating the change in peak correlation value due to delay and the change in EL correlation value due to delay, respectively, using the parameters shown in Non-Patent Document 3.

[0053] Figure 4(a) shows the change in peak correlation value due to delay under the condition of only a calibration signal without an OFDM (Orthogonal Frequency Division Multiplexing) signal. The horizontal axis indicates the delay amount in sample units, with the maximum value at 0, indicating no delay. As shown in Figure 4(a), symmetric correlation values ​​are obtained for positive and negative delay amounts around 0 on the horizontal axis, so that delay amounts of less than one sample can be calculated using the EL correlation value.

[0054] Figure 4(b) shows the change in EL correlation value due to delay when a calibration signal (CAL signal) is superimposed on an OFDM signal (NR signal). The vertical axis of the graph in Figure 4(b) represents the EL correlation value, and the horizontal axis represents the delay in sample units. Under conditions without AWGN (Additive White Gaussian Noise), the function forms a neat linear function passing through the origin (shown by the solid line). Under conditions with AWGN added and an SNR (Signal to Nose power Ratio) of 18 dB, the EL correlation value disperses, as shown by the error bars, and plotting the average value 100 times forms a neat linear function (shown by the dotted line). Using the properties of this EL correlation value, the transmission characteristic comparison unit 353 calculates delay differences of less than one sample between antenna elements, calculates (or determines) the amount of correction for each transmission characteristic (delay) so that all characteristics (delays) are the same, generates a transmission characteristic correction amount signal indicating the amount of transmission characteristic correction, and outputs it to the transmission characteristic correction units 175-1 to 175-N.

[0055] Next, a description will be given of the receiving side of the operation of communication device 100 in Fig. 1. Unless otherwise specified, the following describes the case where preprocessing is performed to perform calibration between antenna elements (i.e., correction by reception characteristic correction units 275-1 to 275-N).

[0056] The reception characteristic calculation analog unit 185 performs transmission processing such as DA conversion and up-conversion on the calibration signal input from the calibration signal generation unit 120, and generates high frequency analog signals for each of the antenna elements 145-1 to 145-N.

[0057] The above-described high-frequency analog signal is an example of a first analog signal in the receiving device and receiving method according to the present disclosure.

[0058] Adders 195-1 to 195-N add each of these high-frequency analog signals to the analog signals (main signals) received by N antenna elements 145-1 to 145-N, respectively, and output the results.

[0059] The analog signals received by (via) the N antenna elements 145-1 to 145-N are an example of second analog signals in the receiving device and receiving method according to the present disclosure.

[0060] The analog signals output from adders 195-1 to 195-N pass through duplexers 140-1 to 140-N, respectively, and are input to power amplifiers 235-1 to 235-N.

[0061] The analog signals output from adders 195-1 to 195-N after each high-frequency analog signal is added to the analog signals received by N antenna elements 145-1 to 145-N are an example of a third analog signal in the receiving device and receiving method according to the present disclosure.

[0062] The power amplifiers 235-1 to 235-N each amplify the power of the input analog signal and output the amplified power to the DCs 230-1 to 230-N.

[0063] The DCs 230-1 to 230-N down-convert the analog signals input from the power amplifiers 235-1 to 235-N from the reception frequency band and output the signals to the ADCs 225-1 to 225-N, respectively.

[0064] The ADCs 225-1 to 225-N convert the analog signals input from the DCs 230-1 to 230-N into digital signals and output them to the transmission and reception characteristic calculation unit 190 and the reception characteristic correction units 275-1 to 275-N, respectively.

[0065] The above digital signal is an example of a first digital signal in the receiving device and receiving method according to the present disclosure.

[0066] DCs 230-1 to 230-N, ADCs 225-1 to 225-N, and power amplifiers 235-1 to 235-N perform reception processing, including at least AD conversion, on analog signals obtained by adding high-frequency analog signals corresponding to calibration signals to analog signals received via N antenna elements 145-1 to 145-N, to generate digital signals.

[0067] At least the DCs 230-1 to 230-N (and possibly the ADCs 225-5 to 225-N and the power amplifiers 235-1 to 235-N) are an example of a reception processing execution unit in the receiving device and receiving method according to the present disclosure.

[0068] The transmission and reception characteristic calculation unit 190 calculates the reception characteristic using the signals input from the ADCs 225-1 to 225-N, generates a reception characteristic correction amount signal, and outputs it to the reception characteristic correction units 275-1 to 275-N.

[0069] The reception characteristic correction units 275-1 to 275-N store in a storage unit (not shown) the reception characteristic (delay) correction amount indicated by the reception characteristic correction amount signal input from the transmission and reception characteristic calculation unit 190. Alternatively, the reception characteristic (delay) correction amount may be stored in a storage unit (not shown) by the transmission and reception characteristic calculation unit 190. When pre-processing for performing inter-antenna element calibration has already been performed in this manner, the reception characteristic correction units 275-1 to 275-N thereafter perform inter-antenna element calibration by correcting the characteristics of the digital signals input from the ADCs 225-1 to 225-N based on the reception characteristic (delay) correction amount indicated by the reception characteristic correction amount signal, and output the calibrated digital signals to the reception digital precoding unit 215.

[0070] A detailed description will be omitted for cases where pre-processing for performing inter-antenna element calibration has already been performed. In this case, analog signals received by N antenna elements 145-1 to 145-N are input to reception characteristic correction units 275-1 to 275-N via the above-mentioned duplexers 140-1 to 140-N, power amplification units 235-1 to 235-N, DCs 230-1 to 230-N, and ADCs 225-1 to 225-N, respectively. Then, the reception characteristic correction units 275-1 to 275-N perform inter-antenna element calibration as described above, and output the calibrated digital signals to the reception digital precoding unit 215.

[0071] The analog signals received by each of the N antenna elements 145-1 to 145-N are an example of a second analog signal in the transmitting device and receiving method according to the present disclosure. Furthermore, at least the DCs 230-1 to 230-N (and possibly the ADCs 225-1 to 225-N and the power amplifiers 135-1 to 135-N) are an example of a second receiving process execution unit in the transmitting device and transmitting method according to the present disclosure.

[0072] The receiving digital precoding unit 215 performs digital precoding on the digital signals that have been subjected to reception characteristic correction input from each of the reception characteristic correction units 275-1 to 275-N, generates L outputs (received streams 1 to L), and outputs them to the received signal regeneration units 210-1 to 210-L.

[0073] As described above, delay measurement by correlation is performed after the reception calibration signal passes through a transmission circuit dedicated to the calibration signal (reception characteristic calculation analog unit 185). That is, unlike Patent Document 2, delay measurement by correlation is performed without the reception calibration signal passing through a delay element in the transmission circuit of the main signal.

[0074] 5 is a diagram showing an example of the configuration of the reception characteristic calculation analog section 185. The reception characteristic calculation analog section 185 includes a DAC 325, a UC 330, a power amplification section 335, and an output changeover switch 337.

[0075] The DAC 325 converts the calibration signal, which is a digital signal input from the calibration signal generating unit 120 , into an analog signal and outputs it to the UC 330 .

[0076] The UC 330 up-converts each analog signal to a transmission frequency band and outputs the up-converted analog signal to the power amplifier 335, similar to the UCs 130-1 to 130-N.

[0077] The power amplifier 335 amplifies the power of the up-converted analog signal input from the UC 330 and outputs the amplified power to the output selector switch 337, similar to the power amplifiers 135-1 to 135-N.

[0078] Output changeover switch 337 sequentially selects one of the outputs to adders 195-1 to 195-N, outputs the analog signal input from power amplifier 335 to the selected adder, and outputs 0 (null) to the other unselected adders.

[0079] The DAC 325, the UC 330, the power amplifier 335, and the output selector switch 337 perform transmission processing including at least DA conversion on the calibration signal to generate an analog signal.

[0080] The analog signal is an example of a first analog signal in the receiving device and receiving method according to the present disclosure. At least the DAC 325 (and possibly the UC 330, the power amplifier 335, and the output selector switch 337, i.e., the reception characteristic calculation analog unit 185) is an example of a transmission processing execution unit or a first transmission processing execution unit in the receiving device and receiving method according to the present disclosure.

[0081] In the transmission / reception characteristic calculation unit 190 shown in FIG. 3, the input selection switch 441 selects the ADC from among the outputs from the ADCs 225-1 to 225-N to which the calibration signal is output from the reception characteristic calculation analog unit 185, and outputs the input from that ADC to the correlation calculation unit 443.

[0082] The correlation calculation unit 443 performs a correlation calculation between the digital signals input from the input selection switches 441 corresponding to the analog signals received by the antenna elements 145-1 to 145-N, respectively, and the pseudo-random sequence generated by the calibration signal generation unit 120 and input from the calibration signal generation unit 120.

[0083] The EL detection unit 447 detects the peak value within one period of the pseudo-random sequence and obtains the desired correlation gain by performing correlation calculations over multiple periods as necessary. The EL detection unit 447 also outputs the EL correlation value, which is the result of subtracting the correlation value one sample after the peak value from the correlation value one sample before the peak value, to the reception characteristic comparison unit 453 as the reception characteristic.

[0084] The output from reception characteristic calculation analog unit 185 is switched sequentially to each of N antenna elements 145-1 to 145-N, and reception characteristic comparison unit 453 compares the characteristics of each of N antenna elements 145-1 to 145-N. Then, using the properties of the EL correlation value shown in Fig. 4(b), reception characteristic comparison unit 453 calculates (or determines) the amount of reception characteristic (delay) correction for each of N antenna elements 145-1 to 145-N so that all characteristics (delays) are the same, generates a reception characteristic correction amount signal indicative of the reception characteristic correction amount, and outputs it to reception characteristic correction units 275-1 to 275-N.

[0085] The transmission and reception characteristic calculation unit 190 is an example of a reception characteristic calculation unit in the receiving device and receiving method according to the present disclosure.

[0086] <Advantages of First Embodiment> According to the first embodiment, with the above configuration, it is possible to provide a transmitting device and a receiving device that maintain constant beamforming performance through delay calibration using the properties of the EL correlation value. In particular, delay measurement by correlation is performed after the transmitting calibration signal and the receiving calibration signal pass through a receiving circuit and a transmitting circuit dedicated to the calibration signal, respectively. That is, unlike Patent Document 2, delay measurement by correlation is performed without the transmitting calibration signal and the receiving calibration signal passing through delay elements in the receiving circuit and the transmitting circuit of the main signal, respectively. Therefore, transmitting delay calibration and receiving delay calibration can be performed independently of each other, which has the effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0087] (Embodiment 2) Fig. 6 is a diagram showing an example of a flowchart of delay calibration between antenna elements (which may also be referred to as systems) in transmission or reception of communication device 100 shown in Fig. 1. Based on this flowchart, communication device 100 can perform delay calibration for transmission and delay calibration for reception independently of each other.

[0088] Particularly when using high frequency bands, the main cause of delay differences between antenna elements is not individual differences in delay characteristics between analog elements, but rather differences in wiring length on the board. Taking advantage of this property, in S101, the communication device 100 (e.g., the control unit, correlation calculation units 343 and 443, EL detection units 347 and 447, transmission characteristic comparison unit 353, or reception characteristic comparison unit 453, etc., not shown in FIG. 1 ) identifies a system having a median delay as a reference system (reference antenna element) based on the wiring length of the board. Alternatively, the reference system may be manually identified by a person, such as a designer, from board information (wiring length of the board). Here, the median delay refers to the median value of the delays of N antenna elements 145-1 to 145-N. In this way, using a system having a median delay as the reference system makes it possible to narrow the range of delay correction amounts compared to Patent Document 2. Note that the reference system is not limited to a system having a median delay, and a system having a delay value close to the median delay may also be used.

[0089] When the communication device 100 identifies the reference system, the wiring length of the board may be stored in a design information database provided in, for example, a storage unit (not shown). The wiring length of the board is an example of design information according to the present disclosure.

[0090] In S201, the correlation calculation unit 343 and the EL detection unit 347 cooperate (in the case of delay calibration for transmission), or the correlation calculation unit 443 and the EL detection unit 447 cooperate (in the case of delay calibration for reception) to perform EL correlation of the reference system.

[0091] In each of S301-1 to S301-N, the correlation calculation unit 343 and the EL detection unit 347 cooperate (in the case of delay calibration of transmission), or the correlation calculation unit 443 and the EL detection unit 447 cooperate (in the case of delay calibration of reception) to perform EL correlation of the systems #1 to #N when the systems #1 to #N are other than the reference system.

[0092] In S401, the transmission characteristic comparison unit 353 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 453 (in the case of delay calibration of reception) compares the EL correlation value of the reference system with the EL correlation values ​​of systems #1 to #N (other than the reference system).

[0093] In S402, the transmission characteristic comparison unit 353 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 453 (in the case of delay calibration of reception) calculates and outputs the delay amounts of the systems #1 to #N (other than the reference system) (more specifically, as a transmission characteristic correction amount signal or a reception characteristic correction amount signal) so as to match the delay characteristics of the other systems to the delay characteristics of the reference system based on the result of the comparison in S401 and the properties of the EL correlation value shown in Fig. 4(b). Then, the flow shown in Fig. 6 ends.

[0094] <Advantages of the Second Embodiment> According to the second embodiment, the above configuration has the effect of narrowing the range of the delay correction amount by identifying a system having a median delay as a reference system and matching the delay characteristics of the other systems to the delay characteristics of the reference system. Also, as in the first embodiment, it is possible to perform delay calibration of transmission and delay calibration of reception independently of each other, and it has the effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0095] (Embodiment 3) Fig. 7 is a diagram showing another example of a flowchart of delay calibration between antenna elements (systems) in transmission or reception of communication device 100 shown in Fig. 1. Based on this flowchart, communication device 100 can perform delay calibration for transmission and delay calibration for reception independently of each other. The same reference numerals are used for the same processes as in the flowchart in embodiment 2, and their explanations will be omitted.

[0096] S101 and S201 are the same as in the second embodiment.

[0097] In S501, the calibration signal generating unit 120 adjusts the delay amount of the calibration signal so that the EL correlation of the reference system becomes zero.

[0098] S301-1 to S301-N are the same as those in the second embodiment.

[0099] In the third embodiment, the process of S401 in the second embodiment is not necessary, and in S412, the transmission characteristic comparison unit 353 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 453 (in the case of delay calibration of reception) calculates and outputs the amount of delay (more specifically, as a transmission characteristic correction amount signal or a reception characteristic correction amount signal) so that the EL correlation of branches #1 to #N (other than the reference branch) becomes 0. Then, the flow shown in Fig. 7 ends.

[0100] <Advantages of the Third Embodiment> According to the third embodiment, the above configuration identifies a system having a median delay as a reference system, and by matching the delay characteristics of the other systems to the delay characteristics of the reference system, it is possible to achieve the effect of narrowing the range of the delay correction amount. Furthermore, unlike the second embodiment, by adjusting the delay amount of the calibration signal so that the EL correlation of the reference system is zero, it is possible to calculate the delay amount so that the EL correlations of systems #1 to #N (other than the reference system) are also zero. This simplifies the processing and further enhances the effect of narrowing the range of the delay correction amount by matching the median value of zero. Furthermore, as in the first and second embodiments, it is possible to perform delay calibration for transmission and delay calibration for reception independently of each other, which also has the effect of halving the time required for delay calibration between antenna elements compared to Patent Document 2.

[0101] (Fourth embodiment) 8 is a diagram showing an example of the configuration of a communication device 500 according to the fourth embodiment of the present disclosure. The same components as those in the communication device 100 according to the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0102] 8 is configured such that a transmission / reception characteristic calculation unit 590 is substituted for the transmission / reception characteristic calculation unit 190 of the communication device 100 according to the first embodiment shown in FIG. 1. The components of the communication device 500 that perform digital processing may be implemented as an integrated circuit 505. The components that perform digital processing include transmission signal generation units 110-1 to 110-M, transmission digital precoding units 115, calibration signal generation units 120, DACs 125-1 to 125-N, reception signal regeneration units 210-1 to 210-L, reception digital precoding units 215, ADCs 225-1 to 225-N, transmission characteristic correction units 175-1 to 175-N, transmission / reception characteristic calculation units 590, and reception characteristic correction units 275-1 to 275-N. The integrated circuit 505 may include not only the components that perform digital processing, but also some or all of the components that perform analog processing.

[0103] Fig. 9 is a diagram showing an example of the configuration of a transmission and reception characteristics calculation unit 590. Compared to the transmission and reception characteristics calculation unit 190 in the first embodiment shown in Fig. 3, the transmission and reception characteristics calculation unit 590 shown in Fig. 9 has a configuration in which the correlation calculation units 343 and 443, the EL detection units 347 and 447, the transmission characteristics comparison unit 353, and the reception characteristics comparison unit 453 are replaced with correlation calculation units 543 and 643, peak detection units 547 and 647, a transmission characteristics comparison unit 553, and a reception characteristics comparison unit 653.

[0104] The correlation calculation units 543 and 643 perform correlation calculations between the digital input signals corresponding to the antenna elements 145-1 to 145-N and the calibration signals (pseudo-random sequences) generated by the calibration signal generation unit 120 and input from the calibration signal generation unit 120 at a high-speed sampling rate (for example, 10 times the transmission sampling rate).

[0105] Peak detectors 547 and 647 detect peak values ​​within one period of the pseudo-random sequence and obtain the desired correlation gain by performing correlation calculations over multiple periods as necessary. Peak detectors 547 and 647 also detect peak timings and output the detected peak timings to transmission characteristic comparator 553 and reception characteristic comparator 653 as transmission (delay) and reception (delay) characteristics, respectively.

[0106] Transmission characteristic comparison unit 553 compares the characteristics (delay) of each of N antenna elements 145-1 to 145-N. Then, transmission characteristic comparison unit 553 calculates (or determines) the amount of transmission characteristic correction for each of N antenna elements 145-1 to 145-N so that all characteristics are the same, generates a transmission characteristic correction amount signal indicating the transmission characteristic correction amount, and outputs it to transmission characteristic correction units 175-1 to 175-N.

[0107] Similarly, reception characteristic comparison unit 653 compares the characteristics (delay) of each of N antenna elements 145-1 to 145-N. Then, reception characteristic comparison unit 653 calculates (or determines) the amount of reception characteristic correction for each of N antenna elements 145-1 to 145-N so that all characteristics are the same, generates a reception characteristic correction amount signal indicating the amount of reception characteristic correction, and outputs it to reception characteristic correction units 275-1 to 275-N.

[0108] <Advantages of the Fourth Embodiment> According to the fourth embodiment, with the above configuration, it is possible to provide a transmitting device and a receiving device that maintain constant beamforming performance through delay calibration using correlation calculations at a high sampling rate. In particular, delay measurement by correlation is performed after the transmitting calibration signal and the receiving calibration signal pass through a receiving circuit and a transmitting circuit dedicated to the calibration signal, respectively. That is, unlike Patent Document 2, delay measurement by correlation is performed without the transmitting calibration signal and the receiving calibration signal passing through delay elements in the receiving circuit and the transmitting circuit of the main signal, respectively. Therefore, transmitting delay calibration and receiving delay calibration can be performed independently of each other, which has the effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0109] (Embodiment 5) Fig. 10 is a diagram showing an example of a flowchart of delay calibration between antenna elements (systems) in transmission or reception of communication device 500 shown in Fig. 8. Based on this flowchart, communication device 500 can perform delay calibration for transmission and delay calibration for reception independently of each other. The same reference numerals are used for the same processes as in the flowcharts of embodiments 2 and 3, and their explanations will be omitted.

[0110] S101 is the same as in the second and third embodiments.

[0111] In S221, the correlation calculation unit 543 and the peak detection unit 547 cooperate (in the case of delay calibration for transmission), or the correlation calculation unit 643 and the peak detection unit 647 cooperate (in the case of delay calibration for reception) to perform correlation of the reference system.

[0112] In each of S321-1 to S321-N, the correlation calculation unit 543 and the peak detection unit 547 cooperate (in the case of delay calibration of transmission), or the correlation calculation unit 643 and the peak detection unit 647 cooperate (in the case of delay calibration of reception) to perform correlation of systems #1 to #N when systems #1 to #N are other than the reference system.

[0113] In S421, the transmission characteristic comparison unit 553 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 653 (in the case of delay calibration of reception) compares the correlation peak timing of the reference system with the correlation peak timing of systems #1 to #N (other than the reference system).

[0114] In S422, the transmission characteristic comparison unit 553 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 653 (in the case of delay calibration of reception) calculates and outputs the delay amounts of the systems #1 to #N (other than the reference system) (more specifically, as a transmission characteristic correction amount signal or a reception characteristic correction amount signal) based on the comparison result in S421 so as to match the delay characteristics of the other systems to the delay characteristics of the reference system. Then, the flow shown in FIG. 10 ends.

[0115] <Advantages of the Fifth Embodiment> According to the fifth embodiment, the above configuration allows a system having a median delay to be identified as a reference system, and the delay characteristics of the other systems to be matched to the delay characteristics of the reference system, thereby achieving the effect of suppressing the range of the delay correction amount. Unlike the second and third embodiments, the correlation calculation is performed at a high-speed sampling rate, thereby eliminating the need for EL correlation. Furthermore, similar to the first to fourth embodiments, the delay calibration of transmission and the delay calibration of reception can be performed independently of each other, which also has the effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0116] (Embodiment 6) Fig. 11 is a diagram showing another example of a flowchart of delay calibration between antenna elements (systems) in transmission or reception of communication device 100 shown in Fig. 1. Based on this flowchart, communication device 100 can perform delay calibration for transmission and delay calibration for reception independently of each other. The same reference numerals are used for the same processes as in the flowcharts of embodiments 2 and 3, and their explanations will be omitted.

[0117] In each of S631-1 to S631-N, the correlation calculation unit 343 and the EL detection unit 347 cooperate (in the case of delay calibration for transmission), or the correlation calculation unit 443 and the EL detection unit 447 cooperate (in the case of delay calibration for reception) to perform EL correlation for systems #1 to #N.

[0118] In S632, the transmission characteristic comparison unit 353 (in the case of delay calibration of transmission) or the reception characteristic comparison unit 453 (in the case of delay calibration of reception) compares the EL correlation values ​​of branches #1 to #N and identifies the branch with the median delay value as the reference branch.

[0119] S201, S301-1 to S301-N, S401 and S402 are the same as those in the second embodiment.

[0120] <Advantages of Sixth Embodiment> According to the sixth embodiment, the above configuration allows a system having a median delay to be identified as a reference system, and the delay characteristics of the other systems to be matched to the delay characteristics of the reference system, thereby achieving an effect of suppressing the range of the delay correction amount. Unlike the second embodiment, the sixth embodiment does not identify the reference system based on the wiring length of the board, but can automatically identify the reference system by performing EL correlation of systems #1 to #N and comparing these correlation values. Furthermore, similar to the first to fifth embodiments, delay calibration of transmission and delay calibration of reception can be performed independently of each other, which also has the effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0121] (Embodiment 7) Fig. 12 is a diagram showing another example of a flowchart of delay calibration between antenna elements (systems) in transmission or reception of communication device 100 shown in Fig. 1. Based on this flowchart, communication device 100 can perform delay calibration for transmission and delay calibration for reception independently of each other. The same reference numerals are used for the same processes as in the flowcharts of embodiments 2 to 6, and their explanations will be omitted.

[0122] 12, S631-1 to S631-N, S632, and S201 are the same as in embodiment 6, and S501, S301-1 to S301-N, and S412 are the same as in embodiment 3. Therefore, in embodiment 7, unlike the flowchart shown in FIG. 7 in embodiment 3, the reference system is automatically identified by performing EL correlation of systems #1 to #N and comparing these correlation values, as in embodiment 6.

[0123] <Effects of the Seventh Embodiment> According to the seventh embodiment, the above configuration allows a system having a median delay to be identified as a reference system, and the delay characteristics of the other systems are adjusted to match those of the reference system, thereby achieving an effect of narrowing the range of the delay correction amount. Unlike the third embodiment, the seventh embodiment does not identify the reference system based on the wiring length of the board, but rather performs EL correlation of systems #1 to #N and compares their correlation values, thereby automatically identifying the reference system. Furthermore, unlike the sixth embodiment, by adjusting the delay amount of the calibration signal so that the EL correlation of the reference system is zero, the delay amount can be calculated so that the EL correlations of systems #1 to #N (other than the reference system) are also zero. This simplifies the processing and further enhances the effect of narrowing the range of the delay correction amount by adjusting the median delay to zero. Furthermore, similar to the first to sixth embodiments, the transmission delay calibration and the reception delay calibration can be performed independently of each other, resulting in an effect of halving the time required for delay calibration between antenna elements compared to Patent Document 2.

[0124] (Embodiment 8) Fig. 13 is a diagram showing another example of a flowchart of delay calibration between antenna elements (systems) in transmission or reception of communication device 500 shown in Fig. 8. Based on this flowchart, communication device 500 can perform delay calibration for transmission and delay calibration for reception independently of each other. The same reference numerals are used for the same processes as in the flowcharts of embodiments 2 to 3 and 5 to 7, and their explanations will be omitted.

[0125] In S641-1 to S641-N, the correlation calculation unit 543 and the peak detection unit 547 work together (in the case of delay calibration for transmission), or the correlation calculation unit 643 and the peak detection unit 647 work together (in the case of delay calibration for reception) to perform correlation of systems #1 to #N.

[0126] In S642, the transmission characteristic comparison unit 553 (in the case of transmission delay calibration) or the reception characteristic comparison unit 653 (in the case of reception delay calibration) compares the correlation peak timings of systems #1 to #N and identifies the system with the median delay as the reference system.

[0127] S221, S321-1 to S321-N, S421 and S422 are the same as in the fifth embodiment.

[0128] <Effects of the Eighth Embodiment> According to the eighth embodiment, the above configuration allows a system having a median delay to be identified as a reference system, and the delay characteristics of the other systems to be matched to the delay characteristics of the reference system, thereby achieving an effect of suppressing the range of the delay correction amount. Unlike the fifth embodiment, the eighth embodiment does not identify the reference system based on the wiring length of the board, but rather performs correlation of systems #1 to #N and compares the correlation peak timings, thereby enabling automatic identification of the reference system. Unlike the sixth to seventh embodiments, the correlation calculation is performed at a high sampling rate, thereby eliminating the need for EL correlation. Furthermore, similar to the first to seventh embodiments, delay calibration of transmission and delay calibration of reception can be performed independently of each other, resulting in an effect of reducing the time required for delay calibration between antenna elements by half compared to Patent Document 2.

[0129] (supplement) The above describes the embodiments with reference to the drawings, but the present disclosure is not limited to the contents described in the above embodiments 1 to 8, and can be implemented in any form that achieves the purpose of the present disclosure and related or incidental purposes, such as the following.

[0130] (1) In the first to eighth embodiments, a full digital beamforming configuration is used, but the present disclosure is not limited to this, and a hybrid beamforming configuration may also be used. In this case, the same effects as those of the above embodiments can be obtained.

[0131] (2) In the first to eighth embodiments, delay calibration may be performed only once or repeatedly. In the latter case, particularly in the second to third and fifth to eighth embodiments, the flowchart is repeated, but the reference system having the median delay may be identified only once at the beginning. In particular, in the second to third and sixth to seventh embodiments, the reference system is identified based on the wiring length of the board, so it is desirable to perform delay calibration only once at the beginning.

[0132] (3) In the first to third and sixth to seventh embodiments, the EL detection unit may perform averaging to improve accuracy. As the averaging method, in addition to simple averaging, for example, IIR (Infinite Impulse Response) may be used.

[0133] (4) In the fourth to eighth embodiments, the peak detection unit may perform averaging to improve accuracy. In addition to simply averaging several samples around the peak, peak detection may be performed using, for example, IIR.

[0134] (5) In the first to sixth embodiments, the transmission characteristic comparison unit and the reception characteristic comparison unit may calculate the delay difference between the reference system and other systems by utilizing the nature of the change in the EL correlation value shown in FIG. 4(b). For example, the nature of the change may be stored in a table and used.

[0135] (6) In the first, third, and seventh embodiments, it is conceivable that the transmission characteristic comparator and the reception characteristic comparator may use the nature of the change in the EL correlation value shown in FIG. 4(b) to calculate the delay amount at which the EL correlation value of each system becomes 0. For example, the nature of the change may be stored in a table and used.

[0136] (7) Some of the first to eighth embodiments may be combined with one another.

[0137] (8) In embodiments 1 to 8, the notation "··· part" used for each component may be replaced with other notations such as "··· circuitry," "··· assembly," "··· device," "··· unit," or "··· module."

[0138] (9) This disclosure may relate to implementations using hardware and software. The above embodiments may be implemented or performed using a computing device (processor). The computing device or processor may be, for example, a main processor / general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device. The above embodiments may be performed or realized by a combination of these devices.

[0139] (10) The first to eighth embodiments may be implemented as software modules executed by a processor or directly by hardware. A combination of software modules and hardware implementation is also possible. The software modules may be stored in various types of computer-readable storage media, such as RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROMs, DVDs, etc.

[0140] (Summary of the embodiment) a transmission processing execution unit that performs transmission processing including digital-to-analog conversion on a second digital signal obtained by adding the digital calibration signal to a first digital signal corresponding to each of the plurality of antenna elements, thereby generating a first analog signal; a reception processing execution unit that performs reception processing including analog-to-digital conversion on the first analog signal that has passed through each of the plurality of antenna elements, thereby generating a third digital signal corresponding to each of the plurality of antenna elements; a transmission characteristic calculation unit that performs a correlation operation between the digital calibration signal and the third digital signal to calculate a transmission characteristic related to delay for each of the plurality of antenna elements, and calculates a transmission characteristic correction amount related to delay for each of the plurality of antenna elements based on the transmission characteristic related to delay; and a transmission characteristic correction unit that corrects the transmission characteristic related to delay based on the transmission characteristic correction amount.

[0141] a receiving device according to an embodiment of the present disclosure, the receiving device including a plurality of antenna elements; a calibration signal generating unit that generates a digital calibration signal; a transmission processing executing unit that performs transmission processing including digital-to-analog conversion on the digital calibration signal to generate a first analog signal; a reception processing executing unit that performs reception processing including analog-to-digital conversion on a third analog signal obtained by adding the first analog signal to a second analog signal received via each of the plurality of antenna elements to generate a first digital signal corresponding to each of the plurality of antenna elements; a reception characteristic calculating unit that performs a correlation operation between the digital calibration signal and the first digital signal to calculate a reception characteristic related to delay for each of the plurality of antenna elements and calculates a reception characteristic correction amount related to delay for each of the plurality of antenna elements based on the reception characteristic related to delay; and a reception characteristic correcting unit that corrects the reception characteristic related to delay based on the reception characteristic correction amount.

[0142] A transmission method according to one embodiment of the present disclosure includes a transmitting device generating a digital calibration signal, performing transmission processing including digital-to-analog conversion on a second digital signal obtained by adding the digital calibration signal to a first digital signal corresponding to each of a plurality of antenna elements included in the transmitting device, thereby generating a first analog signal, and performing reception processing including analog-to-digital conversion on the first analog signal that has passed through each of the plurality of antenna elements, thereby generating a third digital signal corresponding to each of the plurality of antenna elements, performing a correlation operation between the digital calibration signal and the third digital signal, calculating a transmission characteristic related to delay for each of the plurality of antenna elements, calculating a transmission characteristic correction amount related to delay for each of the plurality of antenna elements based on the transmission characteristic related to delay, and correcting the transmission characteristic related to delay based on the transmission characteristic correction amount.

[0143] A receiving method according to one embodiment of the present disclosure includes a receiving device generating a digital calibration signal, performing transmission processing including digital-to-analog conversion on the digital calibration signal to generate a first analog signal, performing reception processing including analog-to-digital conversion on a third analog signal obtained by adding the first analog signal to a second analog signal received via each of a plurality of antenna elements included in the receiving device, thereby generating a first digital signal corresponding to each of the plurality of antenna elements, performing a correlation operation between the digital calibration signal and the first digital signal to calculate a reception characteristic related to delay for each of the plurality of antenna elements, calculating a reception characteristic correction amount related to delay for each of the plurality of antenna elements based on the reception characteristic related to delay, and correcting the reception characteristic related to delay based on the reception characteristic correction amount.

[0144] With the above configuration, after the transmission calibration signal (or reception calibration signal) passes through a first reception processing execution unit (first transmission processing execution unit) dedicated to calibration signals, which is different from the second reception processing execution unit (or second transmission processing execution unit) for reception signals (or transmission signals), delay calibration can be performed by a single transmission-only (or reception-only) correlation. This enables transmission and reception to be performed in parallel, shortening the delay calibration time and achieving high-performance beamforming.

[0145] The transmitting device and receiving device according to the present disclosure may be implemented in a HAPS, a terrestrial base station, or a user terminal. [Industrial Applicability]

[0146] The present disclosure is not limited to HAPS, but can be applied to beamforming technology in wireless transmission. [Explanation of symbols]

[0147] 100, 500 Communication equipment 105, 505 Integrated Circuits 110 Transmission signal generation unit 115 Digital precoding unit for transmission 120 Calibration signal generation section 125, 325 DAC 130, 330 UC 135, 235, 335, 435 Power amplifier section 140 Duplexer 145 antenna elements 175 Transmission characteristic correction section 180 Analog section for calculating transmission characteristics 185 Analog section for calculating reception characteristics 190, 590 Transmission and reception characteristic calculation section 195 Adder 210 Received signal regeneration unit 215 Receiving digital precoding unit 225, 425 ADC 230, 430 DC 275 Reception characteristic correction unit 337 Output selector switch 343, 443, 543, 643 Correlation calculation section 347, 447 EL detector 353, 553 Transmission characteristics comparison section 437, 441 Input selection switch 453, 653 Receiving characteristics comparison section 547, 647 Peak detector

Claims

1. a plurality of antenna elements; a calibration signal generating unit that generates one digital calibration signal; a transmission processing execution unit that performs transmission processing including digital-to-analog conversion on second digital signals obtained by adding the one digital calibration signal to first digital main signals corresponding to each of the plurality of antenna elements to generate first analog signals; a reception processing execution unit that generates a third digital signal corresponding to each of the plurality of antenna elements by performing a reception process including analog / digital conversion on the first analog signal that has passed through each of the plurality of antenna elements; a transmission characteristic calculation unit that calculates a transmission characteristic related to delay for each of the plurality of antenna elements by performing a correlation calculation between the one digital calibration signal and the third digital signal, and calculates a transmission characteristic correction amount related to delay for each of the plurality of antenna elements based on the transmission characteristic related to delay; a transmission characteristic correction unit that corrects the transmission characteristic related to the delay based on the transmission characteristic correction amount; A transmitting device having:

2. the transmission characteristic calculation unit calculates the transmission characteristic related to the delay by performing the correlation calculation to obtain an EL (Early-Late) correlation value; The transmitting device according to claim 1 .

3. the transmission characteristic calculation unit performs the correlation calculation at a high-speed sampling rate to calculate the transmission characteristic related to the delay. The transmitting device according to claim 1 .

4. the transmission characteristic calculation unit calculates a delay-related transmission characteristic correction amount so that the delay-related transmission characteristics of the antenna elements other than the reference antenna element are matched to the delay-related transmission characteristics of a reference antenna element having a median delay among the plurality of antenna elements. The transmitting device according to claim 1 .

5. the calibration signal generation unit adjusts the delay amount of the digital calibration signal so that an E-L correlation value of a reference antenna element having a median delay value among the plurality of antenna elements becomes 0; The transmission characteristic calculation unit calculates a transmission characteristic correction amount related to the delay so that an EL correlation value of an antenna element other than the reference antenna element becomes 0. The transmitting device according to claim 2 .

6. The reference antenna element is identified based on design information. The transmitting device according to claim 4.

7. the transmission characteristic calculation unit identifies the reference antenna element based on the transmission characteristics related to the delay of all of the plurality of antenna elements. The transmitting device according to claim 4.

8. a plurality of antenna elements; a calibration signal generating unit that generates one digital calibration signal; a transmission processing execution unit that performs a transmission process including digital / analog conversion on the one digital calibration signal to generate a first analog calibration signal; a reception processing execution unit that generates first digital signals corresponding to the plurality of antenna elements by performing reception processing including analog-to-digital conversion on third analog signals obtained by adding the first analog calibration signal to second analog signals received via the plurality of antenna elements; a reception characteristic calculation unit that calculates a reception characteristic related to a delay for each of the plurality of antenna elements by performing a correlation calculation between the one digital calibration signal and the first digital signal, and calculates a reception characteristic correction amount related to the delay for each of the plurality of antenna elements based on the reception characteristic related to the delay; a reception characteristic correction unit that corrects the reception characteristic related to the delay based on the reception characteristic correction amount; A receiving device having:

9. The reception characteristic calculation unit calculates the reception characteristic related to the delay by performing the correlation calculation to obtain an E-L correlation value.

9. The receiving device according to claim 8.

10. the reception characteristic calculation unit performs the correlation calculation at a high-speed sampling rate to calculate the reception characteristic related to the delay.

9. The receiving device according to claim 8.

11. the reception characteristic calculation unit calculates a delay-related reception characteristic correction amount so that the delay-related reception characteristics of the antenna elements other than the reference antenna element are matched to the delay-related reception characteristics of a reference antenna element having a median delay among the plurality of antenna elements.

9. The receiving device according to claim 8.

12. the calibration signal generation unit adjusts the delay amount of the digital calibration signal so that an E-L correlation value of a reference antenna element having a median delay value among the plurality of antenna elements becomes 0; The reception characteristic calculation unit calculates a reception characteristic correction amount related to the delay so that an EL correlation value of an antenna element other than the reference antenna element becomes 0.

10. The receiving device according to claim 9.

13. The reference antenna element is identified based on design information.

12. The receiving device according to claim 11.

14. the reception characteristic calculation unit identifies the reference antenna element based on the transmission characteristics related to the delay of all of the plurality of antenna elements.

12. The receiving device according to claim 11.

15. The transmitting device Generate one digital calibration signal; performing a transmission process including digital-to-analog conversion on a second digital signal obtained by adding the one digital calibration signal to a first digital main signal corresponding to each of a plurality of antenna elements included in the transmitting device, thereby generating a first analog signal; generating a third digital signal corresponding to each of the plurality of antenna elements by performing a receiving process including an analog-to-digital conversion on the first analog signal that has passed through each of the plurality of antenna elements; performing a correlation calculation between the one digital calibration signal and the third digital signal to calculate a transmission characteristic related to delay for each of the plurality of antenna elements; calculating a delay-related transmission characteristic correction amount for each of the plurality of antenna elements based on the delay-related transmission characteristic; correcting the transmission characteristic related to the delay based on the transmission characteristic correction amount; Sending method.

16. The receiving device Generate one digital calibration signal; performing a transmission process including digital-to-analog conversion on the one digital calibration signal to generate a first analog calibration signal; generating a first digital signal corresponding to each of the plurality of antenna elements by performing a receiving process including an analog-to-digital conversion on a third analog signal obtained by adding the first analog calibration signal to a second analog signal received via each of the plurality of antenna elements included in the receiving device; performing a correlation calculation between the one digital calibration signal and the first digital signal to calculate a reception characteristic related to delay for each of the plurality of antenna elements; calculating a delay-related reception characteristic correction amount for each of the plurality of antenna elements based on the delay-related reception characteristic; correcting the reception characteristics related to the delay based on the reception characteristics correction amount; Receiving method.

17. A program for causing a transmitting device to execute the transmitting method according to claim 15.

18. A program for causing a receiving device to execute the receiving method according to claim 16.

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