JPH1146180A - Calibration device of array antenna radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the delay characteristic and amplitude characteristic of radio receiving parts by containing a supplying means of a calibration signal and a detecting means which detects at least one of a delay characteristic and an amplitude characteristic from a calibration signal that passes through the radio receiving parts. SOLUTION: A calibration signal which is outputted in a carrier frequency is transmitted from a sending terminal 106 to antenna connection terminals 110 and 111 of radio receiving parts 108 and 109 via a cable 107. A receiving output of each part 108 and 109 is inputted to a synchronous circuit 112 and inverse spread timings t1 and t2 of each radio part are generated. Correlators 113 and 114 perform inverse spreading with the timings t1 and t2 and output correlation outputs 115 and 116. A detection circuit 117 calculates (amplitude ratio and phase difference) = (Ar1 and Δψr1) 118 and (Ar2 and Δψr2) 119 by comparing receiving signals r1 and r2 which are calculated from the outputs 115 and 116 with an identification point that is served as the reference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to direct spread CDMA.
The present invention relates to a calibration apparatus for detecting delay characteristics or amplitude characteristics of a plurality of wireless reception units in an array antenna wireless reception device of a system and correcting the delay characteristics or amplitude characteristics among the wireless reception units so as to be uniform.

[0002]

2. Description of the Related Art There is a multiple access system as a line connection system for simultaneously communicating a plurality of communication stations in the same band, and one of them is a CDMA (Code Division Multiplot).
le Access) method. The CDMA method is a code division multiple access, and is a technique for performing multiple access by spread spectrum communication in which the spectrum of an information signal is spread over a band that is sufficiently wider than the original information bandwidth and transmitted. Also referred to as spread spectrum multiple access (SSMA).
A system in which a spread code is directly multiplied to an information signal to spread a spectrum is called a direct spread system.

[0003] "Waveform equalization technology for digital mobile communication" (supervised by Atsushi Horikoshi, Trikeps Co., Ltd.), in an array antenna composed of a plurality of antennas, the amplitude and phase of the reception output (antenna output) of each antenna. It is disclosed that the directivity of the array changes when a composition is added after adding a shift. The adaptive array antenna system is a system that determines a weight to be multiplied by each antenna output based on a certain control algorithm, and controls directivity while adapting to changes in surrounding conditions.

FIG. 4 shows a configuration of a device for controlling the directivity of a desired signal by using an adaptive array (hereinafter, referred to as a reception adaptive array). In this reception adaptive array, each antenna output 402 output from a plurality of antenna elements 401 is multiplied by a weight 403. A signal obtained by combining the outputs of the antennas multiplied by the weight 403 becomes an array output 404.

[0005] The weight control unit 407 includes: 1) a combined output of the array (405); 2) an output of each antenna (402);
Weight control is performed based on three pieces of information of prior knowledge (406) regarding the desired signal.

[0006] Conventionally, adaptive array antenna systems use SINR (Signal to Interference p
It has been researched and developed as an antenna system that maximizes lus Noise Ratio (signal to interference plus noise).

Further, in the field of direct-sequence CDMA communication, many schemes using an adaptive array antenna have been studied and reported as measures for suppressing interference between other stations. The CDMA system has an advantage that it is more resistant to interference than the FDMA system and the TDMA system. However, with the increase in the number of multiplexing stations, synchronization acquisition becomes difficult, communication quality deteriorates, and communication becomes impossible. . The main cause is
This is because interference between other stations based on cross-correlation characteristics between spreading codes assigned to a plurality of other communication stations is not sufficiently suppressed. In the case of the cellular system of the CDMA system, since there are many other stations using the same frequency in the own cell as well as in other cells, if the suppression of the interference between other stations can be realized, the frequency utilization efficiency can be improved. Thus, the communication quality of each station in the same cell (area) can be improved, and the capacity (the number of multiplexes or the number of line connections) can be increased.

FIGS. 5 and 6 show a configuration example of a CDMA reception adaptive array. In FIG. 5, a reception output 503 of each of a plurality of radio units 502 connected to a plurality of antenna elements 501 is multiplied by a weight 504. Weight 5
An array output 505 is obtained by combining the respective reception outputs 503 multiplied by “04”. Weight control is the same as in FIG. By despreading array output 505 with spreading code 506, received data 507 is obtained.

In FIG. 6, a plurality of antenna elements 60
In this configuration, a correlation output 604 obtained by despreading each reception output 602 from a plurality of wireless units connected to the first unit with a spreading code 603 is input and performing adaptive array reception. The configuration is similar to that of FIG. 2 except for despreading by a spreading code.

FIG. 7 shows an example of CDMA transmission using an adaptive array antenna on the receiving side. Base station (BS: 7
01) has a receiving adaptive array and is communicating with a mobile station (MS1: 702) having an omnidirectional antenna. By controlling the directivity, the BS 701 can eliminate delayed waves (703 and 704) and suppress interference waves from other mobile stations (MS2: 705) using the same frequency.

By the way, in the above CDMA reception adaptive array, generally, the fluctuation amount (D1, d2,..., Dn) composed of the phase fluctuation and the amplitude fluctuation in each radio unit is expressed by
It differs individually due to variations in element delay characteristics and amplitude characteristics of amplifiers and filters, etc., which are components of the radio section.
Therefore, different phase fluctuations and amplitude fluctuations are added to the reception output 503 or 602 in each radio unit. As a result, the phase and amplitude of the received signal wave at the antenna receiving end and the phase and amplitude of the input signal to the weight control unit differ for each antenna. Therefore, the directivity pattern including the null point obtained from the weight convergence result is different from the actual directivity pattern. In addition, when the transmission directivity is controlled using the reception weight, correct directivity control becomes impossible.

As a measure for preventing the above phenomenon, it is essential that the phase difference and the amplitude ratio of the received signal at each antenna receiving end are held even at the stage of the input signal to the weight control unit. For this reason, the delay (D1, d2,
.., Dn) and the amplitude, and it is necessary to compensate for the variation (difference) between the delay amount and the amplitude amount by some method.

One of the methods for compensating for variations in the amount of delay and the amount of amplitude is to use the reception outputs 503,
A method of multiplying 602 by a phase offset corresponding to the delay difference and a gain offset corresponding to the amplitude ratio can be considered. For the detection of variations in the phase and amplitude characteristics of an adaptive array device, see GVTsoulos, MA
Beach "Calibration and Linearity issues for an
Adaptive Antenna System ", IEEE VTC, Phoenix,
pp. 1597-1660, May 1997. However, the above paper is directed to TDMA communication with a narrower communication bandwidth than CDMA communication.
Further, a tone signal is used as a calibration signal.

FIG. 8 shows a conventional calibration device for a radio section in CDMA radio communication. The case where the number of antenna elements is two is shown. Tone signal (sine wave signal) 80 generated from calibration signal generation circuit 801
2 is input to the wireless transmission unit 803. In this example, assuming that orthogonal modulation is performed in the radio section, sin (ωt) and cos (ωt) signals are input as orthogonal I and Q signals. The tone signal period T at this time is T = 2π / ω, and ω = fs / m (m> with respect to the information symbol frequency fs.
1). FIG. 9 shows a constellation of the tone signal on the IQ plane. The signal goes around the circle in the figure at a constant period of 2π / ω. The wireless transmission unit 803 has a function of transmitting at the reception carrier frequency fc of the wireless reception unit that performs delay detection. The signal output at the carrier frequency fc is transmitted from the transmission terminal 804 to the wireless reception unit 80 using a cable or the like.
5,806 antenna connection terminals 807 and 808. At this time, it is assumed that the cable length is equal to the wavelength of the carrier frequency with sufficient accuracy. The quadrature detection outputs 809 and 810 of each wireless reception unit are input to the detection circuit 811. The detection circuit 811, the input tone signal 80
2 and the detection output 809, the (amplitude ratio,
(Phase difference) = (Ar1, Δψr1) 812 is detected. Also, by comparing the tone signal 802 and the detection output 810,
(Amplitude ratio, phase difference) = (Ar2, Δψr2) 813 is detected.
FIG. 10 shows the tone signal a (t) and the detection output b (t) at time t.
Shows an example of the constellation. Then, b (t) and a
The relationship of (t) is expressed as follows using the phase difference ψ and the amplitude ratio A.

B (t) = A ・ exp (jψ) ・ a (t) At this time, the phase difference ψ is the total delay amount Dt of the delay Dt of the radio transmission unit, the cable delay Dk, and the delay Dr of the radio reception unit. (D = Dt
+ Dk + Dr) divided by the tone signal wavelength λ = c / ω (c is the speed of light) and the delay amount (D mod λ: mod is the remainder operator)
(Phase amount). In FIG. 8, two wireless receiving units 80
5,806, the delay Dt and the cable delay Dk of the wireless transmission unit are common, so the detected phase differences Δψr1 and Δψr
2 is the difference between the delay amounts of the wireless receiving units 805 and 806. Further, the amplitude ratio A is the calibration signal 80
2 shows the amplitude ratio of the amplitude of the detection output to the amplitude of the detection output. Therefore,
The ratio between the detected amplitude ratios Ar1 and Ar2 is determined by the radio receiver 805.
And 806 (amplitude ratio) between the amplitude characteristics.

The variation (difference) can be compensated for by detecting the amplitude ratio and the phase difference of each radio section in advance using the above-mentioned device.

[0017]

However, in the above-mentioned calibration apparatus, since the tone signal is used as the calibration signal, the delay characteristic and the amplitude characteristic of only a specific frequency, for example, only the center frequency f0 are measured. Will be. In contrast, the actual CDM
A: When a spread spectrum signal is received because the spread spectrum signal used for wireless communication is a wideband signal, and the amount of delay and attenuation differs depending on the frequency, such as the group delay characteristics and frequency characteristics of filters in the radio section, etc. However, there is a problem that accurate delay characteristics and amplitude characteristics cannot be measured.

FIG. 11 shows a state of a spectrum in a conventional calibration apparatus. Spread signal is center frequency f
It can be seen that while the calibration signal is a line spectrum, it is a broadband signal having a bandwidth M [Hz] of 0.

The present invention has been made in view of the above circumstances, and in detecting a delay characteristic and an amplitude characteristic of a radio unit in a CDMA radio receiving apparatus, the same band or the same as that of a spread spectrum signal used for actual communication. It is an object of the present invention to provide a calibration apparatus for an array antenna wireless communication apparatus that can accurately measure a delay characteristic and an amplitude characteristic of a wireless reception unit by using a signal having a band close thereto as a calibration signal.

[0020]

According to the present invention, at least one of the delay characteristic and the amplitude characteristic of each radio receiving unit is determined by using a calibration signal in the same band as the spread signal used for actual communication or in a band close thereto. Provided is a calibration device that detects and corrects delay characteristics and / or amplitude characteristics of each wireless reception unit.

According to the present invention, since the calibration signal in the same band as the spread signal of the CDMA communication used for the actual communication or a band close to the same band is used, the group delay characteristic and the frequency characteristic of the filter and the like in the radio section are improved. As described above, even if the delay amount and the attenuation amount are different depending on the frequency, it is possible to accurately measure the delay characteristic and the amplitude characteristic when the spread signal is received.

The present invention also provides a primary modulation circuit for primary-modulating a calibration signal, a spread modulation circuit for spreading-modulating the primary-modulated calibration signal, and converting the spread-modulated calibration signal to a reception carrier frequency. Provided is a calibration device that includes a wireless transmission circuit and a transmission path that transmits a calibration signal of the reception carrier frequency to each wireless reception unit.

According to the present invention, a wideband signal similar to a spread signal of CDMA communication used for actual communication can be generated as a calibration signal, and accurate delay characteristics and amplitude characteristics can be measured.

Also, the present invention provides a synchronization detection circuit for detecting a synchronization timing of a calibration signal received by each radio reception unit, a despreading circuit for despreading the received calibration signal at the synchronization timing detected, A calibration apparatus comprising: a detection circuit that detects a delay difference and an amplitude ratio from a reference identification point using each correlation output from each wireless reception unit obtained by spreading.

According to the present invention, the phase and amplitude of the correlation output obtained by despreading the output signal from each radio unit can be detected, so that the wideband signal similar to the spread signal of the CDMA communication used for actual communication can be detected. To detect the delay amount and amplitude at each wireless receiver that received the signal as a calibration signal as the delay difference and the amplitude ratio from the reference identification point, and to measure the accurate delay and amplitude characteristics of the wireless receiver. Can be.

The present invention also provides a comparison circuit for comparing each correlation output between the radio reception units, a detection circuit for detecting a delay difference and an amplitude ratio of each radio reception unit, and outputting the delay difference and the amplitude ratio. Alternatively, there is provided a calibration device further including a storage circuit for storing.

According to the present invention, in order to match a directivity pattern including a null point obtained from a weight convergence result with an actual directivity pattern, a radio signal as an offset value to be multiplied by an output signal of each radio receiving unit is used. The delay difference and the amplitude ratio between the receiving units can be used.

Also, the present invention provides a reception level variable circuit for changing a reception power level input to a radio reception section, and a detection circuit for detecting a delay difference and / or an amplitude ratio of each radio section for each reception power level. A calibration device comprising:

According to the present invention, the delay amount and / or the amplitude difference between the radio units can be obtained in detail according to the received power level, and the delay difference and the amplitude difference in the array antenna radio receiving apparatus can be compensated for by the received power. It is possible to do it accurately according to the level.

Further, the present invention provides a calibration device including a switching circuit for switching a signal input to a radio reception unit to a reception signal from a reception antenna or a calibration signal based on a control signal.

According to the present invention, it is possible to measure the delay characteristics and the amplitude characteristics of the radio receiving unit when necessary, and to compensate even when the delay characteristics and the amplitude characteristics change with time due to the operating environment and the like. It can be done accurately.

Further, the present invention provides a calibration device including a multiplexing circuit for multiplexing a calibration signal with a reception signal from a reception antenna.

According to the present invention, the calibration signal can be multiplexed during communication, and the delay characteristic and the amplitude characteristic can be measured at all times or when necessary.

Further, the present invention provides a calibration device including a switching circuit for switching the input of the received calibration signal output from each radio unit to the synchronization detection circuit and the despreading circuit in a time division manner for each radio reception unit. I do.

According to the present invention, when the delay difference and the amplitude ratio of the plurality of radio receiving units are obtained in a time-division manner, synchronization detection, correlation calculation, phase detection and the like are performed on the input signals to the plurality of radio receiving units. Since it is not necessary to simultaneously perform the amplitude detection, the circuit scale of the calibration device can be reduced.

Further, according to the present invention, a circuit for controlling transmission timing of a calibration signal transmits a transmission timing signal to a synchronization detection circuit, and the synchronization detection circuit obtains a despread timing from the transmission timing of the calibration signal. To provide an optional device.

According to the present invention, by inputting the transmission timing of the spread-modulated calibration signal to the synchronization circuit as a cheat signal, it is not necessary to detect the synchronization from the received signal to generate the despread timing. Thus, the circuit scale of the calibration device can be reduced.

[0038]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a configuration example of a calibration device according to Embodiment 1 of the present invention. FIG. 1 shows a case where the number of antenna elements is two.

In this calibration device, the calibration signal 101 is primary-modulated by the primary modulation circuit 102. In the present embodiment, the modulation method used in the calibration device is the same as that of normal communication, and as an example, QPSK modulation as primary modulation, BPSK modulation as spreading modulation, and quadrature modulation and radio modulation in the radio unit. It is assumed that orthogonal detection is performed. The calibration signal is a fixed signal of all 0s. The primary modulation signal is spread spectrum by a spread code in a spread modulation circuit 103 and input to a radio transmission section 104.

FIG. 3C shows a constellation of the next modulated signal, and FIG. 3B shows a constellation of the spread signal. After the transmission signal is quadrature-modulated in radio transmission section 104, it is up-converted to carrier frequency fc and output from transmission terminal 106. The carrier frequency fc is a reception carrier frequency of the present system (wireless receiver). FIG. 2 shows the spectrum of the calibration signal. The spreading rate and the transmission speed of the calibration signal are set so as to have the same bandwidth as the bandwidth M [Hz] of the transmission signal used during communication. Carrier frequency fc
The calibration signal output at
7, from the transmission terminal 106 to the wireless reception units 108, 1
09 to the antenna connection terminals 110 and 111. At this time, it is assumed that the cable length is equal to the wavelength of the carrier frequency with sufficient accuracy.

The reception output of each radio reception unit is output from the synchronization circuit 112.
And despread timings t1 and t2 for each radio unit
Is generated. Then, the correlators 113 and 114 perform despreading at the timings t1 and t2, and output the correlation outputs 115 and
116 is output. In the detection circuit 117, the correlation output 11
By comparing the received signal point (hereinafter referred to as a reception point) r1 obtained from 5 with a reference discrimination point (hereinafter referred to as a reference discrimination point),
(Amplitude ratio, phase difference) = (Ar1, Δψr1) 118 is obtained. The phase difference determined here is the delay Dt of the wireless transmission unit 104, the delay Dk of the cable 107, and the delay Dr1 of the wireless reception unit 108.
The total delay amount D (D = Dt + Dk + Dr1) is divided by the wavelength λc of the carrier frequency fc. Similarly, by comparing the reception point r2 obtained from the correlation output 116 with the reference identification point, (amplitude ratio, phase difference) =
(Ar2, Δψr2) 119 is obtained. FIG. 3C shows the radio section RX1.
FIG. 3D shows the constellation on the (108) side and FIG. 3D on the side of the radio section RX2 (109) and the amplitude ratio and the phase difference from the reference signal separation point.

As described above, according to the first embodiment, C
A signal having the same bandwidth as a spread signal used in actual spread spectrum communication or a signal having a band close thereto is used as a calibration signal in order to detect delay characteristics and amplitude characteristics of a wireless reception unit in a DMA wireless reception device. Therefore, an accurate delay difference and amplitude ratio can be detected by comparing a correlation output obtained by despreading an output signal from each radio reception unit with a reference identification point.

Further, by multiplying the output signal of each radio reception unit as an offset by the phase difference and amplitude ratio detected for each radio reception unit, the directivity pattern including a null point obtained from the weight convergence result and the actual directivity pattern are obtained. It is also possible to solve the problem that the sex pattern is different.

In the first embodiment, QP is used as primary modulation.
Although BPSK modulation is used as SK modulation and spread modulation, and quadrature modulation and quadrature detection are performed in the radio section, the above-described modulation and detection schemes are not essential in the present invention, and detection is similarly performed in another scheme. It is clear that can be done. It is also clear that it is easy to measure only one of the phase characteristic and the amplitude characteristic.

Note that the detection value does not necessarily need to be the delay difference and the amplitude ratio from the reference identification point, and the offset value between the radio reception units calculated based on the despread correlation output is used as the detection value. Outputting is also conceivable. For example,
In FIG. 1, the correlation outputs 115 and 116 (reception points r1 and r2 in FIGS. 3C and 3D) are represented by position vectors R1 and R2. The detection circuit 117 obtains an offset value when performing compensation for matching the phase characteristics and the amplitude characteristics of the wireless receiving unit to the wireless receiving unit RX1 (108). At this time, assuming that the offset value is a vector Zri (i = 1, 2), it can be expressed as Zr1 = 1 Zr2 = R1 / R2 = R1 × R2 ^* / | R2 | ² (* represents complex conjugate). Then, the above values are output as 118 and 119. It is also conceivable that the calibration apparatus outputs or stores the despread correlation value as it is. In this case, the calculation for obtaining the offset value for compensating for the delay difference and the amplitude difference of each wireless receiving unit using the stored correlation value is performed on the array antenna wireless receiving device side. In the array antenna radio receiving apparatus, the output signals from the radio receiving units RX1 (108) and RX2 (109) are multiplied by the Zr1 and Zr2, thereby compensating for variations in the delay characteristics and the amplitude characteristics. It is possible to prevent the directivity pattern obtained from the convergence result from being different from the actual directivity pattern.

Further, the calibration signal is all
Although a fixed continuous signal of 0 is used, it is apparent that the signal need not be a continuous signal and may be a periodic burst signal. Further, the cable lengths are all assumed to be equal. However, even when the cable lengths are different, if the delay amount and the attenuation amount are known in advance, when the phase difference and the amplitude ratio are detected, the known delay amount and the attenuation amount are used. Can be corrected for. Note that all reference signals (clocks such as a 10 MHz crystal oscillator) used in the radio section are shared.

(Embodiment 2) FIG. 12 shows a configuration example of a calibration apparatus according to Embodiment 2 of the present invention. This is obtained by adding an attenuator (or attenuator) to the calibration device of FIG. As in FIG. 1, the case where the number of antenna elements is two is shown.

FIG. 13 shows one of the delay characteristic Δψri (Pm) and the amplitude characteristic Ari (Pm) of the radio receiver according to the reception electric field level Pm.
An example is shown. In the case of having such delay characteristics and amplitude characteristics, as described in the first embodiment, it is not sufficient to detect the delay amount when the signal is input to the wireless reception unit at a specific reception electric field level. It is necessary to measure the delay characteristic Δψri (Pm) and the amplitude characteristic Ari (Pm) when the reception electric field level Pm is changed.

In FIG. 12, a calibration signal 1201 is primary-modulated by a primary modulation circuit 1202. The primary modulation signal is spread by a spreading code in spreading modulation circuit 1203 and input to radio transmitting section 1204. After the transmission signal is quadrature-modulated in radio transmission section 1204, it is up-converted to carrier frequency fc and output from transmission terminal 1206. fc is the reception carrier frequency of the present system. The signal output at the carrier frequency fc is transmitted from the transmission terminal 1206 to the antenna connection terminals 1211 and 1212 of the wireless reception units 1209 and 1210 using the cable 1208 to which the attenuator 1207 is connected. The reception output of each wireless receiver is input to the synchronization circuit 1213, and despread timings t1 and t2 for each wireless unit are generated. And the above timing t
Correlators 1214 and 1215 perform despreading according to 1, t2, and output correlation outputs 1216 and 1217. The detection circuit 1218 changes the attenuator set value to change the phase difference Δψ when the reception electric field level Pm is changed.
r1 (Pm), Δψr2 (Pm) and amplitude ratios Ar1 (Pm), Ar2 (Pm) are obtained and output or stored.

As described above, according to the embodiment of the present invention, the phase difference Δψr1 corresponding to the difference in the delay amount of the radio receiving unit.
(Pm), Δψr2 (Pm), and the amplitude ratios Ar1 (Pm), Ar2 (Pm) can be finely determined according to the received electric field level. As a result, it is possible to accurately compensate for variations in delay characteristics and amplitude characteristics in the array antenna wireless receiving apparatus according to the received power level.

(Embodiment 3) FIG. 14 shows a configuration example of a calibration apparatus according to Embodiment 3 of the present invention. This is the one in which a changeover switch is added to the calibration device of FIG. As in FIG. 12, the case where the number of antenna elements is two is shown.

In FIG. 14, the calibration signal 1401 is output from the transmission terminal 1406 and until the reception electric field level is changed by the attenuator 1407.
This is the same operation as in FIG. That is, the calibration signal 1401 is primary-modulated by the primary modulation circuit 1402. The primary modulation signal is spread by a spreading code in spreading modulation circuit 1403 and input to radio transmitting section 1404. After the transmission signal is quadrature-modulated in radio transmission section 1404, it is up-converted to carrier frequency fc and output from transmission terminal 1406. The signal output at the carrier frequency fc is transmitted from the transmission terminal 1406 to the changeover switches 1409 and 1410 using the cable 1408 to which the attenuator 1407 is connected.
The switches 1409 and 1410 switch between the received signal from the antenna and the spread signal for calibration by the SW switching signal 1411. Then, the signal from the changeover switch is transmitted to the wireless receiving units 1412 and 1413. The subsequent operation is the same as in FIG. That is, the reception output of each wireless receiving unit is input to the synchronization circuit 1414, and despread timings t1 and t2 for each wireless unit are generated.
Then, the correlator 1415,
1416 performs despreading and outputs correlations 1417 and 1418
Is output. The detection circuit 1419 obtains and outputs phase differences Δψr1 (Pm), Δψr2 (Pm) and amplitude ratios Ar1 (Pm), Ar2 (Pm) when the reception electric field level Pm is changed by changing the attenuator set value. Or remember.

As described above, according to the third embodiment, by controlling the switch signal, it is possible to measure the delay characteristic and the amplitude characteristic of the radio receiving unit when necessary. Accordingly, even when the delay characteristics and the amplitude characteristics change with time due to an operating environment or the like, it is possible to accurately perform compensation.

(Embodiment 4) FIG. 15 shows a configuration example of a calibration apparatus according to Embodiment 4 of the present invention. 13 is obtained by adding a multiplex circuit to the calibration apparatus of FIG. As in FIG. 12, the case where the number of antenna elements is two is shown.

In FIG. 15, the operation is the same as that of FIG. 12 until the calibration signal is output from the transmission terminal and the reception electric field level is changed by the attenuator. That is, the calibration signal 1501 is 1
Primary modulation is performed by the secondary modulation circuit 1502. The primary modulation signal is spread by a spreading code in spreading modulation circuit 1503 and input to radio transmitting section 1504. Wireless transmission unit 1
At 504, the transmission signal is quadrature-modulated, then up-converted to the carrier frequency fc and transmitted to the transmission terminal 1506.
Output. The signal output at the carrier frequency fc is transmitted to a cable 1508 to which an attenuator 1507 is connected.
Are transmitted from the transmission terminal 1506 to the multiplexing circuits 1509 and 1510 via

The multiplexing circuits 1509 and 1510 multiplex the received signal from the antenna and the spread signal for calibration. Then, the multiplexed signal is output to the radio receiving unit 151.
2,1513. The subsequent operation is shown in FIG.
Is the same as That is, the reception output of each wireless receiving unit is input to the synchronization circuit 1514, and despread timings t1 and t2 for each wireless unit are generated. And the above timing t
Correlators 1515 and 1516 perform despreading according to 1, t2, and output correlation outputs 1517 and 1518. The detection circuit 1519 changes the attenuator set value to change the phase difference Δψ when the reception electric field level Pm is changed.
r1 (Pm), Δψr2 (Pm) and amplitude ratio Ar1 (Pm), Ar2 (Pm)
Is output and stored.

As described above, according to the fourth embodiment, it is possible to measure the delay characteristic and the amplitude characteristic of the radio receiving unit constantly or when necessary without interrupting normal communication. Accordingly, even when the delay characteristics and the amplitude characteristics change with time due to an operating environment or the like, it is possible to accurately perform compensation. When the measurement is not performed, it is conceivable to turn off the power of the wireless transmission unit so that the calibration signal serving as a noise component for the received signal is not output at all.

(Fifth Embodiment) FIG. 16 shows an example of the configuration of a calibration device according to a fifth embodiment of the present invention. As in FIG. 12, the case where the number of antenna elements is two is shown. In FIG. 16, the operation is the same as that of FIG. 12 until the calibration signal is output from the transmission terminal and the reception electric field level is changed by the attenuator. That is, the calibration signal 1601 is primary-modulated by the primary modulation circuit 1602. The primary modulation signal is spread by a spreading code in a spreading modulation circuit 1603,
The signal is input to wireless transmission section 1604. Wireless transmission unit 1604
In, after the transmission signal is quadrature-modulated, it is up-converted to the carrier frequency fc and output from the transmission terminal 1606. The signal output at the carrier frequency fc is transmitted from the transmission terminal 1606 to the wireless reception units 1609 and 161 using the cable 1608 to which the attenuator 1607 is connected.
0 is transmitted.

Then, the reception output of each radio reception unit is switched by the changeover switch 1611 and input to the synchronization circuit 1613, and the despread timing ti (i = 1, i = 1,
2) 1614 is output. Also, the changeover switch 161
5 is also switched to select the same received signal as the switch 1611 and outputs the same to the correlator 1616. Then, the correlator 1616 performs despreading at the timing ti,
The correlation output 1617 is output.

In the detection circuit 1618, the attenuator 16
07, the received electric field level
Amplitude ratio Ari (Pm) and phase difference Δψr when Pm is changed
i (Pm) 1619 is obtained and output or stored. Therefore, when the changeover switch 1611 selects the output of the wireless reception unit 1609, the synchronization circuit 1613 outputs the despread timing.
t1 is output, the correlator 1616 performs despreading, and outputs a correlation output 1617. In the detection circuit 1618, the amplitude ratio
Ar1 (Pm) and phase difference Δψr1 (Pm) 1619 are obtained and output or stored. On the other hand, when the changeover switch 1611 selects the output of the wireless receiving unit 1610, the synchronization circuit 16
13 outputs the despread timing t2,
16 performs despreading and outputs a correlation output 1617. In the detection circuit 1618, the amplitude ratio Ar2 (Pm) and the phase difference Δψr
2 (Pm) 1619 is obtained and output or stored.

As described above, according to the fifth embodiment, when the delay characteristics and the amplitude characteristics of a plurality of radio receiving units are obtained in a time-sharing manner by switching a switch, the input signals to the plurality of radio receiving units are obtained. Since it is not necessary to simultaneously perform synchronization detection, correlation calculation, and phase detection, the circuit size of the calibration device can be reduced.

(Sixth Embodiment) FIG. 17 shows a configuration example of a calibration device according to a sixth embodiment of the present invention. As in FIG. 12, the case where the number of antenna elements is two is shown. In FIG. 17, the operation is the same as that of FIG. 12 until the calibration signal is output from the transmission terminal and the reception electric field level is changed by the attenuator. That is, the calibration signal 1701 is primary-modulated by the primary modulation circuit 1702. The primary modulation signal is spread by a spreading code in a spreading modulation circuit 1703,
The signal is input to the wireless transmission unit 1704. Wireless transmission unit 1704
In, after the transmission signal is quadrature-modulated, it is up-converted to the carrier frequency fc and output from the transmission terminal 1706. The signal output at the carrier frequency fc is transmitted to the wireless receiving units 1709 and 1710 using the cable 1708 to which the attenuator 1707 is connected.

At this time, the transmission timing control circuit 171
1 is a primary modulation circuit 1702 and a spread modulation circuit 170
3, the transmission timing signal 1712 is output to control the transmission timing of the spread-modulated calibration signal.

In the present embodiment, the despread timing is generated by extracting the synchronization from the received signal in the first to fifth embodiments, but the transmission timing signal 1712 is used as a cheat signal to synchronize. Circuit 17
13 to generate despread timing. That is, the reception output of each wireless reception unit is synchronized with the synchronization circuit 17.
13, the despread timings t1 and t2
Is generated. The correlators 1714 and 1715 perform despreading at the timings t1 and t2, and output the correlation output 1
1716 and 1717 are output. The detection circuit 1718 changes the attenuator set value to change the phase difference Δψr1 (Pm), Δ
ψ r2 (Pm) and amplitude ratios Ar1 (Pm) and Ar2 (Pm) are obtained and output or stored.

As described above, according to the sixth embodiment, the despread timing is generated by inputting the transmission timing of the spread-modulated calibration signal as a cheat signal to the synchronization circuit. There is no need for a circuit for extracting Therefore, the circuit size of the calibration device can be reduced.

(Seventh Embodiment) FIG. 17 shows a configuration example of a calibration apparatus according to a seventh embodiment of the present invention. As in FIG. 12, the case where the number of antenna elements is two is shown.

Generally, in a CDMA radio communication apparatus, local signals used in a radio transmission unit and a radio reception unit are generated by different synthesizers. When the optimum intermediate frequency used in the up-conversion of the radio transmission unit and the optimum intermediate frequency used in the down-conversion of the radio reception unit are different, the frequency of the local signal used in the radio transmission unit and the frequency of the local signal used in the radio reception unit are made different This is because there is a need.

However, when the local signals used in the radio transmitting unit and the radio receiving unit are different, there is a possibility that the carrier frequency fc on the transmitting side and the receiving side may be slightly shifted. Therefore, when the above phenomenon occurs, the reception phase changes over time even when the delay amount of the radio unit does not change over time. Therefore, when obtaining the phase difference Δψr and the amplitude ratio Ar from the difference between the reference identification point and the receiving point, it is impossible to detect accurate values.

Therefore, according to the present invention, in addition to the calibration device shown in FIG. 12, a local signal (L
o signal) are all common.

In FIG. 18, it is assumed that the local signal 1820 is commonly supplied to all the radio units. Other configurations and operations are the same as those in FIG. That is,
The calibration signal 1801 is output from the primary modulation circuit 18
02 is primarily modulated. The primary modulation signal is spread by a spreading code in spreading modulation circuit 1803 and input to radio transmitting section 1804. After the transmission signal is quadrature-modulated in radio transmission section 1804, carrier frequency fc
And is output from the transmission terminal 1806. The signal output at the carrier frequency fc is transmitted to the wireless receiving units 1809 and 1810 using the cable 1808 to which the attenuator 1807 is connected. Then, the reception output of each wireless reception unit is input to the synchronization circuit 1811,
Despread timings t1 and t2 are generated for each radio unit. The correlator 18 is controlled by the timings t1 and t2.
12, 1813 perform despreading and output correlations 1814, 18
15 is output. The detection circuit 1816 obtains the phase differences Δψr1 (Pm) and Δψr2 (Pm) and the amplitude ratios Ar1 (Pm) and Ar2 (Pm) when the reception electric field level Pm is changed by changing the attenuator set value. Output or store.

As described above, according to the seventh embodiment, by sharing the local signal used by the radio transmission unit and the radio reception unit, the carrier frequency fc on the transmission side and the reception side is
Can be eliminated. As a result, the phase and the amplitude do not change due to factors other than the delay characteristics and the amplitude characteristics of the radio unit, so that an accurate delay amount can be detected.

Note that, as shown in FIG.
Radio transmission section 190 of MA array antenna radio apparatus
It is conceivable that the spread signal output from the receiver 1 is input to the frequency converter 1902, converted into the reception carrier frequency fc, and then transmitted to the radio receiver. This makes it possible to generate a wide-band calibration signal similar to a spread signal used for actual communication with a simple configuration in which only the frequency conversion unit 1902 is provided.

(Eighth Embodiment) FIG. 20 shows a configuration example of a calibration apparatus according to an eighth embodiment of the present invention. This is obtained by adding an interpolation circuit to the apparatus of FIG. As in FIG. 12, the case where the number of antenna elements is two is shown. As shown in FIG. 13 in the second embodiment, when the delay characteristic Δψri (Pm) and the amplitude characteristic Ari (Pm) of the wireless receiving unit according to the reception electric field level Pm are present, the time when Pm is changed It is necessary to measure the delay characteristic Δψri (Pm) and the amplitude characteristic Ari (Pm).

However, in FIG. 12, the phase difference Δψr1 (Pm) and Δψr2 (Pm) when the attenuator set value is changed and the reception electric field level Pm is changed are obtained and output or stored, thereby obtaining the array antenna radio reception. In order to more accurately compensate for variations in delay characteristics and amplitude characteristics in the device according to the received power level, it is necessary to change the attenuator change amount finely and over a wide range. The amount of data to be processed becomes enormous.

Therefore, in the eighth embodiment, in addition to the configuration of the calibration apparatus shown in FIG. 12, interpolation processing is performed by using the actually measured delay difference and amplitude ratio of each radio unit.
A circuit is provided for obtaining a delay difference and an amplitude ratio with respect to a reception power level other than the measured reception power level.

In FIG. 20, a calibration signal 2001 is primary-modulated by a primary modulation circuit 2002. The primary modulation signal is spread by a spreading code in spreading modulation circuit 2003 and input to radio transmitting section 2004. In the radio transmission unit 2004, the transmission signal is quadrature-modulated, up-converted to the carrier frequency fc, and output from the transmission terminal 2006. fc is the reception carrier frequency of the present system. The signal output at the carrier frequency fc is transmitted from the transmission terminal 2006 to the antenna connection terminals 2011 and 2012 of the wireless reception units 2009 and 2010 using the cable 2008 to which the attenuator 2007 is connected. The reception output of each radio receiving unit is input to the synchronization circuit 2013, and despread timings t1 and t2 for each radio unit are generated. And the above timing t
Correlators 2014 and 2015 perform despreading according to 1, t2, and output correlation outputs 2016 and 2017. The detection circuit 2018 changes the attenuator set value to change the phase difference Δψ when the reception electric field level Pm is changed.
r1 (Pm), Δψr2 (Pm), and amplitude ratios Ar1 (Pm), Ar2 (Pm)
Is output.

The interpolation circuit 1219 also obtains a phase characteristic Δψri (Pm) and an amplitude characteristic Ari (Pm) other than the measured received electric field level Pm, and then obtains a phase characteristic Δψri (Pm) and an amplitude characteristic Ari (Pm). Pm) is output. For example, in FIG. 13, the phase difference Δψri (P
0), Δψri (P2), and the amplitude ratios Ari (P0), Ari (P2) are actually measured values. At this time, in the interpolation circuit 1219, the phase characteristic Δψr
i (P1) and the amplitude characteristic Ari (P1) can be obtained by primary linear interpolation as follows.

Δψri (P1) = (t · Δψri (P0) + s · Δψri (P
2)) / (s + t) Ari (P1) = (t · Ari (P0) + s · Ari (P2)) / (s + t) where P1 = (t · P0 + s · P2) / ( s + t), 0 <s, t
<1> As described above, according to the eighth embodiment, the phase difference and the amplitude ratio of the reception electric field level to be compensated are interpolated from the delay characteristic and amplitude characteristic data measured and stored near the reception electric field level to be compensated. It is possible to ask.
Therefore, the delay difference and the amplitude difference in the array antenna radio receiving apparatus can be compensated not only more accurately according to the received electric field level, but also the sample points of the measured reception power level Pm can be reduced.

The measured value used in the interpolation processing does not necessarily need to be the delay difference and the amplitude ratio from the reference identification point, and may be directly calculated based on the despread correlation output.

For example, the correlation output 2016 actually measured
Is represented by a correlation vector Ri (i = 1, 2), and the correlation vectors at the reception electric field levels P0, P2 are Ri (p0), Ri
(p2). In the interpolation circuit 1219, the correlation vector Ri (P1) of the reception electric field level P1 that has not been measured can be obtained by primary linear interpolation as follows.

Ri (P1) = (t · Ri (P0) + s · Ri (P2)) / (s + t) where P1 = (t · P0 + s · P2) / (s + t), 0 <s, t
<1 The phase characteristic ΔPri (P1) and the amplitude characteristic Ari (P1) of the reception electric field level P1 which are not measured can be obtained based on the above Ri (P1). Further, an offset value for performing compensation for matching the phase characteristic and the amplitude characteristic of the wireless receiving unit to the wireless receiving unit RX1 (2009) can be obtained from the correlation vector Ri (P1) obtained by the interpolation processing. That is,
The offset value is defined as a vector Zri (Pm) (i = 1, 2, m = 0, 1,
2, ...), Zr1 (P1) = 1 Zr2 (P1) = R1 (P1) / R2 (P1) = R1 (P1) × R2
(P1) ^* / | R2 (P1) | ² where * can be calculated as representing complex conjugate.

[0083]

As described above in detail, according to the present invention, C
In the detection of the delay characteristic and the amplitude characteristic of the radio unit in the DMA radio receiving apparatus, a signal having the same band or a band close to the same band as the spread spectrum signal used for the actual communication is used as a calibration signal, so that the Delay characteristics and amplitude characteristics can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a calibration device according to a first embodiment of the present invention.

FIG. 2 is a spectrum diagram of a calibration signal according to the first embodiment.

FIG. 3 is a diagram showing a primary modulation signal, a spread signal, and a constellation on the radio unit side according to the first embodiment;

FIG. 4 is a block diagram of a reception adaptive array.

FIG. 5 is a block diagram of a CDMA reception adaptive array.

FIG. 6 is a block diagram of another CDMA reception adaptive array.

FIG. 7: CDMA using a reception adaptive array antenna
Diagram showing transmission example

FIG. 8 is a block diagram of a conventional calibration device.

FIG. 9 shows a constellation of a tone signal.

FIG. 10 is a diagram showing a constellation of transmission / reception signals by a tone signal

FIG. 11 is a spectrum diagram of a calibration signal in a conventional calibration device.

FIG. 12 is a block diagram of a calibration device according to a second embodiment of the present invention.

FIG. 13 is a diagram showing delay characteristics and amplitude characteristics according to a reception electric field level in the second embodiment.

FIG. 14 is a block diagram of a calibration device according to a third embodiment of the present invention.

FIG. 15 is a block diagram of a calibration device according to a fourth embodiment of the present invention.

FIG. 16 is a block diagram of a calibration device according to a fifth embodiment of the present invention.

FIG. 17 is a block diagram of a calibration device according to a sixth embodiment of the present invention.

FIG. 18 is a block diagram of a calibration device according to a seventh embodiment of the present invention.

FIG. 19 is a block diagram of generating a calibration signal using a communication wireless transmission unit according to the seventh embodiment.

FIG. 20 is a block diagram of a calibration device according to an eighth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 Calibration signal 102 Primary modulation circuit 103 Spread modulation circuit 104 Radio transmission unit 106 Transmission terminal 107 Cable 108, 109 Radio reception unit 110, 111 Antenna connection terminal 112 Synchronization circuit 113, 114 Correlator 115, 116 Correlation output 117 Phase detection circuit

Claims (19)

[Claims] An apparatus for calibrating an array antenna radio receiving apparatus, comprising: an array antenna having a plurality of antenna elements; and a plurality of radio receiving sections provided corresponding to each of the antenna elements, for use in spread spectrum communication. Supply means for supplying a calibration signal having substantially the same frequency band as the spread signal to be transmitted to each of the wireless receiving units; and a delay characteristic and an amplitude of the wireless receiving unit from the calibration signal passing through the wireless receiving unit. A calibration device comprising: a detection unit configured to detect at least one of the characteristics. 2. A supply means for primary-modulating a calibration signal, a means for spread-modulating a primary-modulated calibration signal, and a frequency band of the spread-modulated calibration signal to a receiving carrier frequency 2. The calibration apparatus according to claim 1, further comprising: means for transmitting the calibration signal converted to the reception carrier frequency to each of the radio receiving units. 3. A detecting means for detecting a synchronization timing of the calibration signal supplied to the radio receiving unit, and a correlation signal is output by despreading the calibration signal based on the detected synchronization timing. The calibration according to claim 1 or 2, further comprising: means for detecting a phase difference between the correlation signal based on a reference identification point and the correlation signal as a delay amount of a wireless reception unit corresponding to the correlation signal. apparatus. 4. The apparatus according to claim 3, further comprising: means for comparing the amount of delay detected between the wireless receivers to detect a delay difference between the wireless receivers; and means for outputting or storing the delay difference. The calibration device according to item 1. 5. A detecting means for detecting a synchronization timing of the calibration signal supplied to the radio receiving unit, and a correlation signal is output by despreading the calibration signal based on the detected synchronization timing. 3. The calibration according to claim 1, further comprising: means for detecting an amplitude ratio of the correlation signal with respect to a reference identification point as an amplitude ratio of the wireless reception unit corresponding to the correlation signal. apparatus. 6. An apparatus according to claim 5, further comprising: means for comparing an amplitude ratio detected between the wireless receiving units to detect an amplitude difference between the wireless receiving units; and means for outputting or storing the amplitude difference. The calibration device according to item 1. 7. The supply means includes means for changing a power level of a calibration signal supplied to the wireless reception unit, and the detection means causes the supply means to change the calibration signal to a plurality of power levels. The calibration device according to any one of claims 1 to 4, wherein the delay characteristic of each wireless reception unit is detected for each received power level. 8. The supply means includes means for changing a power level of a calibration signal to be supplied to the radio receiving unit, and the detection means causes the supply means to change the calibration signal to a plurality of power levels. 7. The calibration device according to claim 1, wherein the amplitude characteristic of each wireless reception unit is detected for each reception power level. 9. A signal which is arranged between an antenna element and the radio receiving unit corresponding to the antenna element, wherein a signal input to the radio receiving unit is supplied from a reception signal output from the antenna element and supplied from the supply unit. 9. The calibration apparatus according to claim 1, further comprising: means for switching between a calibration signal and a calibration signal. 10. A multiplexing device which is arranged between an antenna element and the radio receiving unit corresponding to the antenna element and multiplexes a reception signal output from the antenna element and a calibration signal supplied from the supply unit. The calibration device according to any one of claims 1 to 8, further comprising means. 11. A synchronizing circuit for detecting the synchronization of a reception signal including a calibration signal output from a radio reception unit by an array antenna radio reception apparatus; 11. The device according to claim 1, further comprising: a despreading circuit that performs despreading, and a unit that switches a signal input to the synchronization circuit and the despreading circuit in a time-division manner for each wireless reception unit. Calibration device. 12. A means for generating a transmission timing signal for giving a transmission timing of a calibration signal to be supplied to a wireless receiving unit, and obtaining a despreading timing of the calibration signal output from the wireless receiving unit from the transmission timing signal. The calibration device according to any one of claims 1 to 10, further comprising means for performing calibration. 13. A radio transmission unit including a signal generation source for generating a local signal, wherein the radio transmission unit and the radio reception unit for up-converting a calibration signal to a reception carrier frequency use a local signal generated from the signal generation source. 13. The calibration device according to claim 1, wherein the calibration device performs frequency conversion. 14. The supply means has means for changing a power level of a calibration signal to be supplied to the wireless reception unit, and the detection means has changed the calibration signal to a plurality of power levels by the supply means. 2. The calibration apparatus according to claim 1, wherein, in the case, a delay characteristic value and an amplitude characteristic value of each wireless unit corresponding to a power level other than the measured power level are obtained by an interpolation process based on an actually measured value. . 15. A detecting means for despreading a calibration signal output from a radio receiving unit to output a correlation signal, and a delay difference and an amplitude ratio of the radio receiving unit by directly using the correlation signal. The calibration apparatus according to claim 1, further comprising: means for executing a compensation operation. 16. A delay amount of each of the wireless receiving units with respect to an array antenna wireless receiving apparatus having an array antenna having a plurality of antenna elements and a plurality of wireless receiving units provided corresponding to each of the antenna elements. In the delay detection device for detecting the spread signal used for spread spectrum communication, a supply unit for supplying a calibration signal having substantially the same frequency band to each of the wireless receiving units, and the wireless unit passing through the wireless receiving unit A delay detecting device for detecting a delay amount of the wireless receiving unit from a calibration signal. 17. An amplitude characteristic of each radio receiving unit for an array antenna radio receiving apparatus having an array antenna having a plurality of antenna elements and a plurality of radio receiving units provided corresponding to each of the antenna elements. In the amplitude detecting device for detecting the spread signal used for spread spectrum communication, a supply unit for supplying a calibration signal having substantially the same frequency band to each of the wireless receiving units, and A detection unit for detecting an amplitude characteristic of the wireless reception unit from a calibration signal. 18. A base station apparatus comprising: an array antenna having a plurality of antenna elements; and an array antenna radio receiving apparatus having a plurality of radio receiving sections provided corresponding to the antenna elements. A base station device comprising the calibration device according to claim 15. 19. A method for calibrating an array antenna radio receiving apparatus having an array antenna having a plurality of antenna elements and a plurality of radio receiving sections provided corresponding to the antenna elements, the method being used for spread spectrum communication. Generating a calibration signal having substantially the same frequency band as the spread signal to be spread; supplying the calibration signal to each of the wireless receiving units; and from the calibration signal that has passed through the wireless receiving unit. Detecting at least one of a delay characteristic and an amplitude characteristic of the wireless reception unit.