JP2006086894A - Radio transmitting circuit, radio receiving circuit and radio equipment of array antenna system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio transmitting circuit and a radio receiving circuit with less phase variation at the time of gain variation in AGC control and TPC control. <P>SOLUTION: A gain controller 104 performs the TPC control by controlling a gain of a transmission signal together with a gain controller 106. A mixer 105 applies frequency conversion to an output signal of the gain controller 104 by a local signal with a frequency higher than a radio frequency outputted by a local oscillator 110. The transmission signal subjected to the frequency conversion is amplified by an amplifier 107 after passing through the gain controller 106 and wirelessly transmitted by an antenna 109 after its band restriction by a filter 108. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio transmission circuit, a radio reception circuit, and an array antenna type radio apparatus using the same.

  In recent years, in radio communication systems, it has been pointed out that there is a shortage of frequency bands used as resources due to high frequency, high speed transmission and diversification, and various methods for improving frequency efficiency have been proposed as a solution. ing.

  As one example, there is an adaptive array antenna wireless device as disclosed in Patent Document 1, for example. This adaptive array antenna type radio apparatus is a radio apparatus that includes a plurality of radio units, and controls antenna directivity by performing phase and amplitude weighting processing on signals transmitted and received via the radio units. In such an adaptive array antenna type radio apparatus, the antenna directivity can be adaptively changed to improve the signal-to-interference ratio of signals to be transmitted and received, and the frequency utilization of the radio communication line to be used can be improved. Efficiency and quality can be increased.

  Patent Document 2 discloses a wireless reception circuit used for a wireless device. The wireless receiving circuit of Patent Document 2 performs AGC (Auto Gain Control) control of a received signal level on a signal received by an antenna using a gain variable unit and a variable gain unit, and converts a radio frequency to a lower frequency by a mixer. And receiving.

  Patent Document 3 discloses a wireless transmission circuit used in a wireless device. The wireless transmission circuit of Patent Document 3 performs TPC (Transmit Power Control) control using a variable gain controller and a variable gain controller, and performs frequency conversion to a radio frequency using a mixer.

  When the conventional radio reception circuit and radio transmission circuit are used in an adaptive array antenna type radio apparatus, there are the following problems. When the variable gain unit is controlled for AGC control or TPC control in each radio transmission / reception circuit, a phase change occurs according to the gain change. Therefore, in the AGC operation when the amplitude weighting in the variable gain unit is performed between the plurality of transmission circuits, or when there is a difference in the reception signal level between the plurality of reception circuits, between each transmission circuit or between the reception circuits. If the control values of the gain controllers are different, a phase error occurs. In a wireless device of an adaptive array antenna system, when a phase error occurs between radio transmission circuits and between radio reception circuits, an error occurs in weighting processing, and the antenna directivity is greatly impaired as the phase error increases.

  One method for correcting these phase errors is disclosed in Patent Document 4. FIG. 7 is a diagram of a wireless transmission / reception circuit used in an adaptive array antenna wireless device described in Patent Document 4.

  In FIG. 7, the signal received by the antenna 10 passes through the antenna duplexer 11, undergoes AGC control, frequency conversion, and the like by the reception RF circuit 15, and is converted from an analog signal to a digital signal by the A / D converter 16. Then, the signal receiving unit 17 performs processing such as demodulation. The transmission signal output from the signal transmission unit 14 is converted from a digital signal to an analog signal by the D / A converter 13, and TPC control, frequency conversion, and the like are performed by the transmission RF circuit 12. 11 and output from the antenna 10.

  In the radio transmission / reception circuit of FIG. 7, the following operation is performed in order to correct phase errors due to AGC and TPC of the plurality of transmission RF circuits 12 and reception RF circuits 15.

The transmission signal output from the transmission RF circuit 12 is subjected to AGC control and the like by the reception RF circuit 15, passes through the A / D converter 16, and is received by the signal reception unit 17. The reference signal generated by the reference signal generator 21 passes through the switch 20 and the antenna duplexer 11, undergoes AGC control and the like in the reception RF circuit 15, passes through the A / D converter 16, Received by the receiving unit 17. The operation is performed for all TPC control values and AGC control values, and the phase fluctuation amount by the AGC control of the reception RF circuit 15 and the phase fluctuation amount by the transmission RF circuit 12 are respectively calculated based on the received transmission signal and the reference signal. The correction value is calculated and stored in the memory 18, and phase error calibration between the wireless transmission circuits and between the wireless reception circuits is performed based on the correction value.
JP-A-9-219615 JP 2000-261332 A Japanese Patent Laid-Open No. 10-93367 International Publication No. 00/60757 Pamphlet

  However, since the phases of the wireless reception circuit and the non-transmission circuit described in Patent Document 2 and Patent Document 3 change when the gain changes in AGC control or TPC control, the wireless antenna of the adaptive array antenna system described in Patent Document 4 is used. In order to use the wireless transmission / reception circuit in the apparatus, it is necessary to store the correction value in the memory. is there.

  The present invention has been made in view of such a point, and an object thereof is to provide a wireless transmission circuit and a wireless reception circuit with small phase fluctuations at the time of gain change in AGC control and TPC control. It is another object of the present invention to provide an array antenna type radio apparatus that can reduce the size of the circuit and reduce power consumption by including the radio transmission circuit and the radio reception circuit.

  The radio transmission circuit of the present invention includes a first gain controller that controls a gain of a transmission signal, and a transmission signal whose gain is controlled by the first gain controller using a local signal having a frequency higher than the radio frequency. A frequency converter that converts the frequency of the transmission signal, and a second gain controller that controls the gain of the transmission signal whose frequency has been converted by the frequency converter, and the first gain controller and the first gain controller The gain controller of 2 adopts a configuration in which the phase fluctuation at the time of gain change is substantially the same.

  The radio reception circuit of the present invention includes a first gain controller that controls the gain of a received signal, and a received signal whose gain is controlled by the first gain controller using a local signal having a frequency higher than the radio frequency. A frequency converter that converts the frequency of the received signal, and a second gain controller that controls a gain of the received signal whose frequency has been converted by the frequency converter, and the first gain controller and the first gain controller The gain controller of 2 adopts a configuration in which the phase fluctuation at the time of gain change is substantially the same.

  The array antenna type radio apparatus of the present invention employs a configuration having at least one of the radio transmission circuit and the radio reception circuit.

  According to the present invention, since a local signal higher than the radio frequency is used in the frequency converter in the radio transmission circuit and the radio reception circuit, AGC control in the first gain controller and the second gain controller, The phase fluctuation caused by the gain change due to the TPC control becomes the reverse phase, and the phase fluctuation amount at the time of the gain change in the first and second gain controllers becomes almost the same amount. Phase fluctuation as a wireless transmission / reception circuit can be reduced. In addition, in an array antenna wireless device, the circuit can be reduced in size and power consumption can be reduced by including the wireless transmission circuit or the wireless reception circuit.

  The essence of the present invention is that the frequency converter performs frequency conversion using a local signal having a frequency higher than the radio frequency, and a gain controller having substantially the same phase fluctuation at the time of gain change is provided at the front and rear stages of the frequency converter. Thus, the phase variation at the time of gain change is reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of radio transmission circuit 100 according to Embodiment 1 of the present invention.

  The radio transmission circuit 100 includes a baseband unit 101, a quadrature modulation unit 102, an amplifier 103, a gain controller 104, a mixer 105, a gain controller 106, an amplifier 107, a filter 108, a local oscillator 110, Have

  The baseband unit 101 is a component that generates an I signal and a Q signal that become transmission signals when signal modulation, TPC control, and quadrature modulation are performed. For example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array) This is realized by a digital signal processing circuit.

  The quadrature modulation unit 102 performs quadrature modulation on the I signal and Q signal output from the baseband unit 101 and outputs the result to the amplifier 103. The amplifier 103 amplifies the output signal of the quadrature modulation unit 102 and outputs the amplified signal to the gain controller 104. The quadrature modulation unit 102 and the amplifier 103 are realized by a transistor IC.

  The gain controller 104 performs TPC control by controlling the gain of the transmission signal together with the gain controller 106. For example, when changing the gain of −10 dB, the gain controller uses −5 dB, The controller 106 controls the -5 dB gain. The gain controller 104 and the gain controller 106 have substantially the same phase variation due to a gain change, and are realized by, for example, a digital attenuator IC.

  The mixer 105 performs frequency conversion on the output signal of the gain controller 104 using a local signal having a frequency higher than the radio frequency output from the local oscillator 110. The mixer 105 is realized by a mixer IC using transistors, and the local oscillator 110 is realized by an oscillation circuit such as a frequency synthesizer using a voltage controlled oscillator (VCO) controlled by a phase negative feedback control system (PLL), for example. .

  The frequency-converted transmission signal passes through the gain controller 106, is amplified by the amplifier 107, band-limited by the filter 108, and then wirelessly transmitted from the antenna 109. For example, the amplifier 107 is realized by a transistor IC, and the filter 108 is realized by a filter module using a dielectric.

The operation of the wireless transmission circuit 100 configured as described above will be described. Transmission signals (I signal and Q signal) generated by the baseband unit 101 are orthogonally modulated by the orthogonal modulation unit 102. The signal S (t) after quadrature modulation is expressed by the following equation (1).
S (t) = A (t) sin (ωift) (1)

Thereafter, the signal is amplified by G1 dB by the amplifier 103 and input to the gain controller 104. The gain controller 104 is controlled by the baseband unit 101. If the desired gain control amount of the entire transmission circuit is N dB, the gain controller 104 controls the N / 2 dB gain. Assuming that the phase fluctuation amount in the gain controller 104 at this time is + α °, the signal S1 (t) after gain control is expressed by the following equation (2).
S1 (t) = 10 ^{(G1 + N / 2) / 10} A (t) sin (ωift + α) (2)

  FIG. 2A shows the above expression (2) as a vector diagram. The signal S1 (t) is input to the mixer 105 and subjected to frequency conversion using the local signal output from the local oscillator 110. The frequency of the local signal is higher than the radio frequency (RF signal) output from the antenna 109. FIG. 3 shows the frequency relationship represented by the frequency axis. The frequency of the transmission signal S1 (t) is an intermediate frequency (IF signal).

A signal S2 (t) obtained by performing frequency conversion using the local signal is expressed by the following equation (3).
S2 (t) = 10 ^{(G1 + N / 2) / 10} A (t) sin (ωift + α) × sin (ωLot)
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωLot) − (ωift + α))
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωLo−ωif) t − α)
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωrf) t − α) (3)
* Ωrf ＝ ωLo − ωif

  FIG. 2B shows the above expression (3) as a vector diagram. The signal S2 (t) whose phase is shifted by + α ° with respect to the original signal S (t) becomes −α ° with respect to the original signal S (t) after frequency conversion.

The signal S2 (t) is input to the gain controller 106, and the N / 2 dB gain is controlled. Assuming that the phase fluctuation amount at this time is + β °, the signal S3 (t) after gain control is expressed by the following equation (4).
S3 (t) = 10 ^{(G1 + N / 2 + N / 2) / 10} A (t) sin (ωrf) t−α + β)
= 10 ^{(G1 + N) / 10} A (t) sin (ωrft −α + β) (4)

  FIG. 2C shows the above expression (4) as a vector diagram. In the above equation (4), if the phase fluctuation + α ° of the gain controller 104 and the phase fluctuation + β ° of the gain controller 106 are substantially the same, the magnitude is in phase with α≈β. −α + β≈0, so that phase fluctuations are almost cancelled. In addition, the gain control amount is a desired gain control amount NdB.

  The signal S3 (t) is amplified by the amplifier 107, band-limited by the filter 108, and then wirelessly transmitted from the antenna 109.

  FIG. 4A is a diagram showing a phase variation amount of a typical digital attenuator, and FIG. 4B is a diagram showing the phase variation amount at the time of gain control in the conventional radio transmission circuit and the radio of this embodiment. It is a figure which shows the amount of phase fluctuations at the time of gain control in a transmission circuit. In the conventional wireless transmission circuit, the amount of phase fluctuation at 40 dB change is about 40 degrees. However, in the wireless transmission circuit of the present embodiment, the amount of phase fluctuation at the time of 40 dB change is canceled because almost the same amount of phase fluctuation is canceled out. It turns out that becomes small with about 9 degree.

  As described above, according to the present embodiment, the frequency converter (mixer) performs frequency conversion using a local signal having a frequency higher than the radio frequency, and the phase change at the time of gain change at the front stage and the rear stage of the frequency converter. By providing the gain controllers having substantially the same amount, the phase fluctuations in the respective gain controllers cancel each other, so that a radio transmission circuit having a small phase fluctuation during TPC control can be configured.

(Embodiment 2)
FIG. 5 is a block diagram showing a configuration of radio receiving circuit 200 according to Embodiment 2 of the present invention.

  The radio transmission circuit 200 includes a baseband unit 201, an orthogonal demodulation unit 202, an amplifier 203, a gain controller 204, a mixer 205, a gain controller 206, an LNA (Low Noise Amplifier) 207, a filter 208, And a local oscillator 210.

  The received signal received by the antenna 209 is band-limited by the filter 208 and amplified by the LNA 207. For example, the LNA 207 is realized by a transistor IC, and the filter 208 is realized by a filter module using a dielectric.

  The gain controller 206 performs AGC control by controlling the gain of the received signal together with the gain controller 204. For example, when changing the gain of −10 dB, the gain controller 204 sets −5 dB, The gain controller 206 controls the -5 dB gain. The gain controller 204 and the gain controller 206 have substantially the same phase variation due to a gain change, and are realized by, for example, a digital attenuator IC.

  The mixer 205 performs frequency conversion on the signal output from the gain controller 206 using a local signal having a frequency higher than the radio frequency output from the local oscillator 210. The mixer 205 is realized by a mixer IC using transistors, and the local oscillator 210 is realized by an oscillation circuit such as a frequency synthesizer using a voltage controlled oscillator (VCO) controlled by a phase negative feedback control system (PLL), for example.

  The frequency-converted received signal passes through the gain controller 204, is amplified by the amplifier 203, is orthogonally demodulated by the orthogonal demodulator 202, and is output to the baseband unit 201 as an I signal and a Q signal.

  The baseband unit 201 is a component having a function of demodulating data from an I signal and a Q signal and a function of performing AGC control. For example, digital signal processing such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Realized with a circuit.

  The operation of the radio reception circuit 200 configured as described above will be described. The reception signal input to the antenna 209 is band-limited by the filter 208, amplified by G1 dB by the LNA 207, and input to the gain controller 206.

The signal S (t) amplified by the LNA 207 is expressed by the following equation (5).
S (t) = 10 ^{(G1) / 10} A (t) sin (ωrft) (5)

The gain controller 206 is controlled by the baseband unit 201. If the desired gain control amount of the entire receiving circuit is NdB, the gain controller 206 controls the N / 2 dB gain. Assuming that the phase fluctuation amount in the gain controller 206 at this time is + α °, the signal S1 (t) after gain control is expressed by the following equation (6).
S1 (t) = 10 ^{(G1 + N / 2) / 10} A (t) sin (ωift + α) (6)

  FIG. 2A shows the above equation (6) as a vector diagram. The signal S1 (t) is input to the mixer 205 and subjected to frequency conversion using the local signal output from the local oscillator 210. The frequency of the local signal is higher than the radio frequency (RF frequency) when input from the antenna 209. FIG. 3 shows the frequency relationship represented by the frequency axis. The frequency of the signal S1 (t) is a radio frequency (RF signal).

A signal S2 (t) obtained by performing frequency conversion using the local signal is expressed by the following equation (7).
S2 (t) = 10 ^{(G1 + N / 2) / 10} A (t) sin (ωrft + α) × sin (ωLot)
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωLot) − (ωift + α))
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωLo−ωrf) t − α)
= 10 ^{(G1 + N / 2) / 10} A (t) sin (ωif) t − α) (7)
* Ωif ＝ ωLo − ωrf

  FIG. 2B shows the above expression (7) as a vector diagram. The signal S2 (t) whose phase is shifted by + α ° with respect to the original signal S (t) becomes −α ° with respect to the original signal S (t) after frequency conversion.

The signal S2 (t) is input to the gain controller 204 and the N / 2 dB gain is controlled. The amount of phase fluctuation at this time is + α ° because it does not depend on the frequency of the signal. The signal S3 (t) output from the gain controller 204 is expressed by an equation.
S3 (t) = 10 ^{(G1 + N / 2 + N / 2) / 10} A (t) sin (ωrf) t−α + β)
= 10 ^{(G1 + N) / 10} A (t) sin (ωrft − α + β) (8)

  FIG. 2C shows the above equation (8) as a vector diagram. In the above equation (8), if the phase fluctuation + α ° in the gain controller 206 and the phase fluctuation + β ° in the gain controller 204 are substantially the same, the magnitude is in phase with α≈β. , −α + β≈0, and the phase fluctuations are almost cancelled. In addition, the gain control amount is a desired gain control amount NdB.

  Thereafter, the signal S3 (t) is amplified by the amplifier 203, quadrature demodulated by the quadrature demodulator 202, and output as an IQ signal to the baseband unit 201 for signal processing such as data demodulation.

  FIG. 4A is a diagram showing a phase variation amount of a typical digital attenuator, and FIG. 4B is a diagram showing the phase variation amount at the time of gain control in the conventional radio receiving circuit and the radio of this embodiment. It is a figure which shows the amount of phase fluctuations at the time of gain control in a receiving circuit. In the conventional radio reception circuit, the amount of phase fluctuation at 40 dB change is about 40 degrees. However, in the radio reception circuit of the present embodiment, the amount of phase fluctuation at the time of 40 dB change is canceled because almost the same amount of phase fluctuation cancels out. It turns out that becomes small with about 9 degree.

  As described above, according to the present embodiment, the frequency converter (mixer) performs frequency conversion using a local signal having a frequency higher than the radio frequency, and the phase change at the time of gain change at the front stage and the rear stage of the frequency converter. By providing the gain controllers having substantially the same amount, the phase fluctuations in the respective gain controllers cancel each other, so that a radio receiving circuit having a small phase fluctuation during the AGC control can be configured.

(Embodiment 3)
FIG. 6 is a diagram showing a configuration of an array antenna radio apparatus according to Embodiment 3 of the present invention. A radio apparatus 300 illustrated in FIG. 6 includes a plurality of radio transmission circuits 100 described in Embodiment 1, a plurality of radio reception circuits 200 described in Embodiment 2, a baseband unit 301, and a plurality of array antennas 302. Have

  Note that the array antenna 302 may be configured to be shared by the wireless transmission circuit 100 and the wireless reception circuit 200 using an antenna duplexer.

  As described above, according to the present embodiment, the wireless device 300 can achieve the same operational effects as the wireless transmission circuit of the first embodiment and the wireless reception circuit of the second embodiment. The phase fluctuation due to TPC control of the transmission circuit and the phase fluctuation due to AGC control in the reception circuit can be reduced, and the memory and signal processing procedure for calibrating the phase error can be reduced. As a result, the circuit size of the array antenna apparatus can be reduced and the power consumption can be reduced.

  The present invention is suitable for use in an array antenna type radio apparatus.

1 is a block diagram showing a configuration of a wireless transmission circuit according to a first embodiment of the present invention. Orthogonal plane coordinate diagram representing signal vectors of the first and second embodiments of the present invention The figure which shows the frequency structure of the signal of Embodiment 1 and Embodiment 2 of this invention (A) The figure which shows the phase variation amount of a typical digital attenuator (b) The phase variation amount at the time of gain control in the conventional radio transmission circuit and the phase variation amount at the time of gain control in the radio transmission circuit of this embodiment Illustration A block diagram showing a configuration of a wireless reception circuit according to a second embodiment of the present invention FIG. 3 is a block diagram showing a configuration of an array antenna radio apparatus according to Embodiment 3 of the present invention. The figure which shows the radio | wireless apparatus of the conventional adaptive array antenna system

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless transmission circuit 101, 201, 301 Baseband part 102 Orthogonal modulation part 103, 107, 203 Amplifier 104, 106, 204, 206 Gain controller 105, 205 Mixer 108, 208 Filter 109, 209, 302 Antenna 110, 210 Local part Oscillator 200 Wireless reception circuit 202 Quadrature demodulation unit 207 LNA
300 Array antenna type wireless device 302 Array antenna

Claims (3)

  A first gain controller for controlling the gain of a transmission signal, and a frequency converter for converting the frequency of the transmission signal whose gain is controlled by the first gain controller using a local signal having a frequency higher than a radio frequency. And a second gain controller for controlling the gain of the transmission signal whose frequency has been converted by the frequency converter, wherein the first gain controller and the second gain controller A wireless transmission circuit characterized in that phase variations at the time of change are substantially the same.   A first gain controller for controlling the gain of the received signal and a frequency converter for converting the frequency of the received signal whose gain is controlled by the first gain controller using a local signal having a frequency higher than the radio frequency And a second gain controller for controlling the gain of the received signal whose frequency has been converted by the frequency converter, wherein the first gain controller and the second gain controller A radio receiving circuit characterized in that phase variations at the time of change are substantially the same.   An array antenna type radio apparatus comprising at least one of the radio transmission circuit according to claim 1 or the radio reception circuit according to claim 2.

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