JP6395782B2 - Communication satellite and system - Google Patents

Description

  The present invention relates to a beam control device, a program, and a communication satellite.

A satellite-mounted multi-beam antenna device that performs mutual communication with a ground terminal by repeatedly using a frequency band has been known (for example, see Patent Document 1).
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP 2009-171308 A

  A technique that can appropriately form a multi-beam has been desired.

  According to a first aspect of the present invention, a beam control device is provided. The beam control apparatus may include a BF execution unit that executes beam forming (may be described as BF) based on a control value for controlling the directivity of the beam. The beam control apparatus may include a signal acquisition unit that acquires a signal input to the antenna after the process executed after the beamforming process. The beam control apparatus may include a component deriving unit that derives a component corresponding to the control value from the signal. The beam control apparatus may include a comparison unit that compares the control value with the component. The BF execution unit may execute the beam forming process based on the comparison result by the comparison unit.

  The comparison unit may generate correction data based on the control value and the component, and the BF execution unit may execute the beam forming process based on the control value and the correction data. The process executed after the beam forming process may be a power amplification process. The control value may include an amplitude value and a phase value. The beam control apparatus may further include a signal transmission unit that transmits a signal output from the BF execution unit to a communication satellite, and the signal acquisition unit performs post-processing of the beam forming process executed in the communication satellite. Thereafter, a signal input to the antenna of the communication satellite may be received from the communication satellite.

  According to the 2nd aspect of this invention, the program for functioning a computer as said beam control apparatus is provided.

  According to a third aspect of the present invention, there is provided a communication satellite comprising the beam control device and the antenna. The beam control device may include a main beam control unit including the BF execution unit, and a spare beam control unit including the signal acquisition unit, the component derivation unit, and the comparison unit.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An example of communication satellite 100 is shown roughly. An example of a functional composition of control device 200 is shown roughly. An example of composition of control device 200 is shown roughly. An example of a functional configuration of a DBF (Digital Beam Former) -DC (Digital Channelizer) 300 is schematically shown. The control device 200 includes a spare DBF-DC 350 and a DBF-DC 300 having the same configuration as the DBF-DC 300, and shares the functions of the DBF-DC 300 shown in FIG. 4 between the DBF-DC 300 and the spare DBF-DC 350. An example is shown schematically. An example in which the functions of the DBF-DC 300 shown in FIG. 4 are shared by the communication satellite 120 and the feeder link station 400 is schematically shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 schematically shows an example of a communication satellite 100. The communication satellite 100 includes an antenna 110 and a control device 200. The antenna 110 is a multi-beam antenna that can form a multi-beam. The antenna 110 is, for example, a phased array antenna.

  The control device 200 forms a plurality of beams 102 using the antenna 110. The control device 200 may be built in the communication satellite 100. Control device 200 may be separate from communication satellite 100.

  Each of the plurality of beams 102 may be assigned a frequency band different from that of an adjacent beam, and the same frequency band may be assigned to some of the plurality of beams 102. That is, the same frequency band may be used repeatedly. The communication satellite 100 transmits a plurality of communication signals to the ground using a plurality of beams 102.

  The communication satellite 100 may receive a plurality of communication signals from a feeder link station arranged on the ground, perform excitation distribution control on the plurality of communication signals, and radiate from the antenna 110. For example, the communication satellite 100 performs BF processing on a plurality of communication signals using weighting factors, performs processing such as frequency conversion and power amplification, and radiates from the antenna 110.

  The communication satellite 100 may receive a weighting factor from the feeder link station. The weighting factor may include an amplitude value and a phase value. The weighting factor may be an example of a control value that controls the directivity of the beam. The weighting coefficient may be called an excitation coefficient, a DBF (Digital Beam Forming) coefficient, or the like.

  The communication satellite 100 according to the present embodiment inputs a reference signal that is a non-modulated wave in addition to the communication signal to the BF execution unit that executes the BF process, and after the process executed after the BF process, the antenna 110 receives the signal. Extract the input signal. The communication satellite 100 derives a component corresponding to the weighting factor from the extracted signal, and compares the component with the weighting factor used for the BF processing. Then, the communication satellite 100 executes the subsequent BF process based on the comparison result.

  For example, the communication satellite 100 calculates the rate of change between the weighting factor used for the BF process and the derived component. The communication satellite 100 derives correction data for correcting the weighting factor in advance so that a result obtained by multiplying the weighting factor received thereafter by the change rate becomes equal to the weighting factor. Then, the communication satellite 100 executes the subsequent BF process after correcting the weighting coefficient with the correction data.

  Even when the BF processing is performed accurately, it is different from the desired control state at the stage radiated from the antenna 110 due to the influence of errors and distortions in subsequent processing such as frequency conversion and power amplification. As a result, the radiation area and side lobes of the beam formed on the ground may be deformed. For example, when areas using the same frequency overlap due to deformation, interference occurs and communication quality deteriorates. On the other hand, according to the communication satellite 100 according to the present embodiment, it is possible to eliminate the influence of error and distortion in the processing executed after the BF processing.

  FIG. 2 schematically illustrates an example of a functional configuration of the control device 200. The control device 200 includes a reception unit 202, a BF execution unit 204, a process execution unit 206, an antenna input unit 208, a signal extraction unit 210, a component derivation unit 212, and a comparison unit 214. The control device 200 may be an example of a beam control device.

  The receiving unit 202 receives a communication signal. The receiving unit 202 may receive a plurality of communication signals transmitted by the feeder link station. The receiving unit 202 receives a reference signal. The receiving unit 202 may receive a plurality of reference signals transmitted by the feeder link station. The frequencies of the plurality of reference signals may be different from each other. The receiving unit 202 receives a weighting factor. The receiving unit 202 may receive a plurality of weighting factors transmitted by the feeder link station.

  The BF execution unit 204 executes BF processing on the communication signal and the reference signal received by the reception unit 202 using the weighting coefficient received by the reception unit 202. The BF execution unit 204 may adjust the amplitude and phase of the communication signal and the reference signal using the weighting factor.

  The process execution unit 206 executes the process after the BF process. The process execution unit 206 executes, for example, a frequency conversion process. The process execution unit 206 may execute an up-conversion process. For example, when the frequency of the signal output from the BF execution unit 204 is 100 MHz, the process execution unit 206 up-converts the signal to 2 GHz. The said numerical value is an illustration and may be another value.

  The process execution unit 206 executes, for example, power amplification processing. The process execution unit 206 may amplify the signal after the BF process by the BF execution unit 204 using a linear region and a saturation region. The process execution unit 206 may amplify the signal after the BF process by the BF execution unit 204 using only the linear region.

  The antenna input unit 208 inputs the signal processed by the processing execution unit 206 to the antenna 110. The antenna input unit 208 may radiate a plurality of beams 102 from the antenna 110 by inputting a signal to the antenna 110.

  The signal extraction unit 210 extracts a signal input to the antenna input unit 208 after the processing by the processing execution unit 206. The signal extraction unit 210 may be a directional coupler, for example.

  The component deriving unit 212 derives a component corresponding to the weight coefficient from the signal extracted by the signal extracting unit 210. The component deriving unit 212 performs, for example, a down-conversion process opposite to the up-conversion process performed by the process execution unit 206 on the signal extracted by the signal extraction unit 210. For example, when up-conversion from 100 MHz to 2 GHz has been performed, the component derivation unit 212 performs a down-conversion process from 2 GHz to 100 MHz. Then, the component deriving unit 212 combines the down-converted signals so that the bandwidth equivalent to the frequency bandwidth of the communication signal received by the receiving unit 202 is obtained. Then, the component deriving unit 212 obtains the amplitude and phase at the frequency of the reference signal from the combined signal, and derives a component corresponding to the weight coefficient.

  The comparing unit 214 compares the weighting factor received by the receiving unit 202 with the component derived by the component deriving unit 212. Based on the comparison result, the comparison unit 214 may generate correction data for correcting the weighting coefficient received by the reception unit 202 thereafter.

  For example, the comparison unit 214 calculates a rate of change between the amplitude value of the received weighting factor and the amplitude value of the derived component. Then, the comparison unit 214 sets the amplitude value of the weighting coefficient so that the result obtained by multiplying the amplitude value of the weighting coefficient received by the receiving unit 202 by the change rate is equal to the amplitude value of the weighting coefficient. A correction coefficient to be corrected is calculated.

  Further, the comparison unit 214 calculates a rate of change between the phase value of the received weighting factor and the phase value of the derived component. The comparison unit 214 then sets the weight coefficient phase value so that the result of multiplying the weight coefficient phase value received by the receiving unit 202 by the change rate is equal to the weight coefficient phase value. A correction coefficient to be corrected in advance is calculated.

  The comparison unit 214 transmits the calculated correction coefficient to the BF execution unit 204. After receiving the correction coefficient from the comparison unit 214, the BF execution unit 204 multiplies the weighting coefficient received from the reception unit 202 by the correction coefficient and executes BF processing. As a result, it is possible to eliminate the influence of distortion and error generated in the communication signal due to the processing by the processing execution unit 206, and it is possible to bring the control state at the stage radiated from the antenna 110 closer to the desired control state. .

  FIG. 3 schematically shows an example of the configuration of the control device 200. The control device 200 includes a DBF-DC 300, a U / C (Up Converter) 232, an HPA (High Power Amplifier) 234, a directional coupler 240, a D / C (Down Converter) 252, and a COMB (Combiner) 254.

  The DBF-DC 300 has a digital beam forming function and a digital channelizing function. The digital channelizing function may be a function of demultiplexing signals from the feeder link station, rearranging them on the frequency axis, and outputting them to the service link.

  The DBF-DC 300 receives a communication signal, a reference signal, and a weighting factor transmitted by the feeder link station. The DBF-DC 300 performs A / D conversion on the communication signal and the reference signal, performs beam forming processing using a weighting factor, performs D / A conversion, and outputs the result.

  The DBF-DC 300 may output signals corresponding to the plurality of beams 102. When the antenna 110 is a phased array antenna, the DBF-DC 300 may output the same number of signals as the number of antenna elements of the antenna 110.

  The U / C 232 up-converts the signal received from the DBF-DC 300 and outputs it. When the antenna 110 is a phased array antenna, the U / C 232 may be installed in parallel by the number of antenna elements of the antenna 110.

  The HPA 234 performs power amplification processing on the signal received from the U / C 232 and outputs the result. The HPA 234 amplifies the signal using, for example, both a linear region and a saturation region. The HPA 234 may amplify the signal using only the linear region of the linear region and the saturation region. When the antenna 110 is a phased array antenna, the HPA 234 may be installed in parallel by the number of antenna elements of the antenna 110. A plurality of signals output by the HPA 234 are input to the antenna 110. Instead of the HPA 234, an MPA (Multi Port Amplifier) having a duplexer, a plurality of HPAs, and a multiplexer may be used. Thereby, the load of HPA can be equalized.

  The directional coupler 240 extracts a signal before being input to the antenna 110 and inputs the signal to the D / C 252. When the antenna 110 is a phased array antenna, the directional coupler 240 may be installed in parallel by the number of antenna elements of the antenna 110.

  The D / C 252 down-converts the signal received from the directional coupler 240 and outputs it. When the antenna 110 is a phased array antenna, the D / C 252 may be arranged in parallel by the number of antenna elements of the antenna 110.

  The COMB 254 combines and outputs a plurality of signals received from the D / C 252. The COMB 254 may group a plurality of signals received from the D / C 252 into a frequency bandwidth equivalent to the frequency bandwidth of the communication signal input to the DBF-DC 300. The COMB 254 inputs the combined signal as a feedback signal to the DBF-DC 300. The DBF-DC 300 performs beam forming processing based on the feedback signal. The DBF-DC 300 may be an example of a beam control device.

  The antenna control apparatus 200 may further include a predistorter function that gives an inverse characteristic of the nonlinear characteristic of the HPA 234 to the signal input to the HPA 234. The antenna control apparatus 200 may include, as an analog process, a predistorter that gives a reverse characteristic of the nonlinear characteristic of the HPA 234 to a signal input to the HPA 234 at the rear stage of the DBF-DC 300 and at the front stage of the HPA 234. . Further, the DBF-DC 300 may execute a process of giving a reverse characteristic of the nonlinear characteristic of the HPA 234 to the signal input to the HPA 234 as a digital process. When MPA is used instead of HPA 234, antenna control apparatus 200 may have a predistorter function corresponding to MPA.

  FIG. 4 schematically shows an example of the functional configuration of the DBF-DC 300. The DBF-DC 300 includes a signal acquisition unit 302, a weighting factor acquisition unit 304, an A / D (Analog / Digital) conversion and IQ (In-phase Quadrature) demodulation unit 306, an FFT (Fast Fourier Transform) processing unit 308, a switch 310, Beam forming unit 312, IFFT (Inverse Fast Fourier Transform) processing unit 314, IQ modulation and D / A conversion unit 316, feedback signal acquisition unit 322, A / D conversion and IQ demodulation unit 324, FFT processing unit 326, weighting factor derivation A unit 328 and a weight coefficient comparison correction unit 330.

  The signal acquisition unit 302 acquires a communication signal and a reference signal. The weighting factor acquisition unit 304 acquires a weighting factor.

  The A / D conversion and IQ demodulation unit 306 performs A / D conversion and IQ demodulation on the communication signal and reference signal acquired by the signal acquisition unit 302. The FFT processing unit 308 performs FFT processing on the signal received from the A / D conversion and IQ demodulation unit 306. The switch 310 distributes the data output by the FFT processing unit 308 for each of a plurality of beams to be formed.

  The beamforming unit 312 performs beamforming processing on the data received from the switch 310 using the weighting factor received from the weighting factor acquisition unit 304. The beam forming unit 312 may be an example of a BF execution unit.

  The IFFT processing unit 314 performs IFFT processing on the data received from the beam forming unit 312. The IQ modulation and D / A conversion unit 316 performs IQ modulation and D / A conversion on the signal received from the IFFT processing unit 314.

  The feedback signal acquisition unit 322 acquires a feedback signal from the COMB 254. The A / D conversion and IQ demodulation unit 324 performs A / D conversion and IQ demodulation on the feedback signal acquired by the feedback signal acquisition unit 322. The FFT processing unit 326 performs FFT processing on the signal received from the A / D conversion and IQ demodulation unit 324.

  The weighting factor deriving unit 328 acquires the amplitude and phase at the frequency of the reference signal for the data received from the FFT processing unit 326, and derives a component corresponding to the weighting factor. The weight coefficient comparison / correction unit 330 compares the weight coefficient received from the weight coefficient acquisition unit 304 with the component received from the weight coefficient derivation unit 328 to generate correction data.

  The beam forming unit 312 receives the correction data generated by the weight coefficient comparison correction unit 330. After receiving the correction data, the beam forming unit 312 corrects the weighting factor received from the weighting factor acquisition unit 304 with the correction data, and executes the beamforming process.

  5, the control device 200 includes a spare DBF-DC 350 and a DBF-DC 300 having the same configuration as the DBF-DC 300. The functions of the DBF-DC 300 shown in FIG. An example of sharing with is shown schematically.

  In the example illustrated in FIG. 5, the backup DBF-DC 350 executes processing by the feedback signal acquisition unit 322, the A / D conversion and IQ demodulation unit 324, the FFT processing unit 326, and the weighting factor derivation unit 328. In the control device 200 shown in FIG. 5, the DBF-DC 300 may be an example of this beam control unit, and the backup DBF-DC 350 may be an example of a backup beam control unit. In the control device 200 shown in FIG. 5, the beamforming unit 312 included in the DBF-DC 300 functions as a BF execution unit, and the feedback signal acquisition unit 322, the weighting factor deriving unit 328, and the weighting factor comparison and correction unit included in the backup DBF-DC350. 330 may function as a signal acquisition unit, a component derivation unit, and a comparison unit. Reducing the processing load of the DBF-DC 300 by causing the spare DBF-DC 350 to execute a process for deriving a component corresponding to the weighting coefficient, a process for deriving correction data by comparing the derived component and the weighting coefficient, and the like. Can do.

  Note that the sharing of the functional configuration illustrated in FIG. 5 is an example, and at least one of the processes by the feedback signal acquisition unit 322, the A / D conversion and IQ demodulation unit 324, the FFT processing unit 326, and the weighting factor derivation unit 328 is performed by DBF. -DC300 may execute. Further, backup DBF-DC 350 may further execute processes other than feedback signal acquisition section 322, A / D conversion and IQ demodulation section 324, FFT processing section 326, and weighting coefficient derivation section 328.

  FIG. 6 schematically shows an example in which the functions of the DBF-DC 300 shown in FIG. 4 are shared by the communication satellite 120 and the feeder link station 400. Communication satellite 120 may include antenna 110, U / C 232, HPA 234, directional coupler 240, D / C 252, and COMB 254.

  In the example illustrated in FIG. 6, the communication satellite 120 includes a feedback signal acquisition unit 322, an A / D conversion and IQ demodulation unit 324, an FFT processing unit 326, and a weight coefficient derivation unit 328. Also, the feeder link station 400 includes a signal acquisition unit 302, a weight coefficient acquisition unit 304, an A / D conversion and IQ demodulation unit 306, an FFT processing unit 308, a switch 310, a beam forming unit 312, an IFFT processing unit 314, IQ modulation and It has a D / A conversion unit 316 and a weight coefficient comparison correction unit 330.

  The feeder link station 400 may include a signal transmission unit (not shown) that transmits the signal resulting from the IQ modulation and D / A conversion unit 316 to the communication satellite 120. The communication satellite 120 may include a signal reception unit (not shown) that receives a signal transmitted by the signal transmission unit of the feeder link station 400 and inputs the signal to the U / C 232.

  The communication satellite 120 may include a signal transmission unit (not shown) that transmits a component corresponding to the weighting factor derived by the weighting factor deriving unit 328 to the feeder link station 400. The feeder link station 400 may include a signal receiving unit (not shown) that receives a component corresponding to the weighting factor transmitted by the signal transmitting unit of the communication satellite 120 and inputs the component to the weighting factor comparison / correction unit 330.

  As illustrated in FIG. 6, among the functions of the DBF-DC 300 illustrated in FIG. 4, the signal acquisition unit 302, weighting factor acquisition unit 304, A / D conversion and IQ demodulation unit 306, FFT processing unit 308, switch 310, beam The feeder link station 400 includes a forming unit 312, an IFFT processing unit 314, an IQ modulation and D / A conversion unit 316, and a weight coefficient comparison and correction unit 330, a feedback signal acquisition unit 322, an A / D conversion and IQ demodulation unit 324, The communication satellite 120 may include an FFT processing unit 326 and a weight coefficient deriving unit 328.

  6 is merely an example, and at least one of the feedback signal acquisition unit 322, the A / D conversion and IQ demodulation unit 324, the FFT processing unit 326, and the weighting factor derivation unit 328 is used as the feeder link station 400. May be provided. The communication satellite 120 may further include a configuration other than the feedback signal acquisition unit 322, the A / D conversion and IQ demodulation unit 324, the FFT processing unit 326, and the weight coefficient derivation unit 328.

  Further, the feeder link station 400 may include all the configurations of the DBF-DC 300 illustrated in FIG. In this case, the feeder link station 400 includes a signal transmission unit that transmits a signal resulting from processing by the IQ modulation and D / A conversion unit 316 to the communication satellite 120, and a signal reception unit that receives a feedback signal from the COMB 254 from the communication satellite 120. May be provided.

  In the above description, each unit of the control device 200 may be realized by hardware or may be realized by software. Further, it may be realized by a combination of hardware and software. Further, the computer may function as the control device 200 by executing the program. The program may be installed in a computer constituting at least a part of the control device 200 from a computer-readable medium or a storage device connected to a network.

  A program that is installed in a computer and causes the computer to function as the control device 200 according to the present embodiment may work on a CPU or the like to cause the computer to function as each unit of the control device 200. The information processing described in these programs is read by a computer, so that the receiving unit 202, the BF execution unit 204, and the processing execution are specific means in which software and hardware resources of the control device 200 cooperate. Functions as a unit 206, an antenna input unit 208, a signal extraction unit 210, a component derivation unit 212, and a comparison unit 214. And the specific control apparatus 200 according to the intended use is constructed | assembled by implement | achieving the calculation or processing of the information according to the intended use of the computer in this embodiment by these specific means. Note that the program according to the present embodiment is installed in a computer including the reception unit 202, the processing execution unit 206, and the antenna input unit 208, so that the BF execution unit 204, the signal extraction unit 210, and the component derivation unit 212 are installed. And the comparator 214 may function. In addition, the program according to the present embodiment is installed in a computer including the reception unit 202, the processing execution unit 206, the antenna input unit 208, and the signal extraction unit 210, thereby making the computer a BF execution unit 204 and a component derivation unit 212. And the comparator 214 may function.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

100 communication satellite, 102 beam, 110 antenna, 120 communication satellite, 200 control device, 202 reception unit, 204 BF execution unit, 206 processing execution unit, 208 antenna input unit, 210 signal extraction unit, 212 component derivation unit, 214 comparison unit 232 U / C, 234 HPA, 240 Directional coupler, 252 D / C, 254 COMB, 300 DBF-DC, 302 Signal acquisition unit, 304 Weight coefficient acquisition unit, 306 A / D conversion and IQ demodulation unit, 308 FFT processing unit, 310 switch, 312 beam forming unit, 314 IFFT processing unit, 316 IQ modulation and D / A conversion unit, 322 feedback signal acquisition unit, 324 A / D conversion and IQ demodulation unit, 326 FFT processing unit, 328 weight Coefficient derivation unit, 330 Weight coefficient comparison correction unit, 350 Preliminary DB F-DC, 400 Feederlink station

Claims (6)

A first BF execution unit that executes beam forming processing based on a control value that controls the directivity of the beam;
A first signal acquisition unit for acquiring a signal input to the antenna after the processing executed after the beamforming processing executed by the first BF execution unit ;
A first component deriving unit for deriving a component corresponding to the control value from the signal acquired by the first signal acquiring unit ;
And a first comparing unit for comparing the component the first component deriving unit and the control value is derived,
The first BF execution unit executes the beam forming process on the basis of the comparison result by the first comparator unit, and the beam control unit,
A second BF execution unit that executes beam forming processing based on a control value that controls the directivity of the beam;
A second signal acquisition unit for acquiring a signal input to the antenna after the processing executed after the beamforming processing executed by the second BF execution unit;
A second component deriving unit for deriving a component corresponding to the control value from the signal acquired by the second signal acquiring unit;
A second comparison unit that compares the control value with the component derived by the second component deriving unit;
Including
The second BF execution unit executes a beam forming process based on a comparison result by the second comparison unit;
With the antenna
With
The second signal acquisition unit acquires a signal input to the antenna after processing executed after the beamforming processing executed by the first BF execution unit,
The first BF execution unit is a communication satellite that executes a beamforming process based on a comparison result by the second comparison unit . The second comparison unit generates correction data based on the control value and the component,
The communication satellite according to claim 1, wherein the first BF execution unit executes the beam forming process based on the control value and the correction data. The communication satellite according to claim 1 or 2, wherein the process executed after the beam forming process is a power amplification process. The communication satellite according to claim 3, wherein the power amplification process amplifies a signal after the beam forming process using a linear region and a saturation region. The communication satellite according to any one of claims 1 to 4, wherein the control value includes an amplitude value and a phase value. A communication satellite,
With feeder link station
A system comprising:
The feeder link station
A BF execution unit that executes a beam forming process based on a control value that controls the directivity of the beam;
A signal transmission unit for transmitting the signal output by the BF execution unit to the communication satellite;
The control value derived by the communication satellite from the signal input to the antenna of the communication satellite after processing executed in the communication satellite on the signal transmitted by the signal transmission unit to the communication satellite A signal receiving unit for receiving a corresponding component from the communication satellite;
A comparator for comparing the control value with the component received by the signal receiver;
With
The BF execution unit executes a beam forming process based on a comparison result by the comparison unit .