WO2016129590A1 - Dispositif de communication sans fil et mode de fonctionnement - Google Patents

Dispositif de communication sans fil et mode de fonctionnement Download PDF

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Publication number
WO2016129590A1
WO2016129590A1 PCT/JP2016/053791 JP2016053791W WO2016129590A1 WO 2016129590 A1 WO2016129590 A1 WO 2016129590A1 JP 2016053791 W JP2016053791 W JP 2016053791W WO 2016129590 A1 WO2016129590 A1 WO 2016129590A1
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signal
distortion compensation
input
feedback
predetermined number
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PCT/JP2016/053791
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English (en)
Japanese (ja)
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泰 山尾
岳林 馬
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国立大学法人電気通信大学
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Priority to JP2016574808A priority Critical patent/JP6730609B2/ja
Publication of WO2016129590A1 publication Critical patent/WO2016129590A1/fr

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion

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  • the present disclosure relates to a wireless communication device and an operation method, and more particularly, to a wireless communication device and an operation method that can be reduced in cost and size.
  • an up-converter or an amplifier included in a transmission circuit of a wireless communication device has non-linearity, and when a wireless signal modulated so that the amplitude changes with time is transmitted from the wireless communication device. , Intermodulation (IM) distortion due to non-linearity occurs. Therefore, a nonlinear compensation technique that suppresses the occurrence of intermodulation distortion sufficiently low is important.
  • a non-linear compensation technique a pre-distortion method is used in which a signal input to a non-linear circuit is distorted in advance so as to be the inverse characteristic of the non-linear input / output characteristic of the non-linear circuit.
  • FIG. 1 is a diagram showing a configuration example of a conventional digital predistortion nonlinear compensation type transmission circuit.
  • a conventional transmission circuit 11 includes a DPD (Digital Pre-Distorter) 12, a DAC (Digital To Analog Converter) 13, an up-converter 14, a local oscillator 15, a power amplifier 16, and a coupler 17. , A down converter 18, an ADC (Analog to Digital Converter) 19, and a parameter adjustment unit 20.
  • DPD Digital Pre-Distorter
  • DAC Digital To Analog Converter
  • the input signal x input to the transmission circuit 11 is preliminarily distorted so as to compensate for the nonlinearity of the power amplifier 16 by the DPD 12 and is output from the DPD 12 as a distortion compensation signal v.
  • the distortion compensation signal v is analog converted by the DAC 13, mixed with the local oscillation frequency f L of the local oscillator 15 by the up converter 14, up-converted to the radio frequency f, and power amplified by the power amplifier 16.
  • the distortion of the distortion compensation signal v applied by the DPD 12 is restored, and an output signal having the same waveform as the input signal x is output from the power amplifier 16.
  • the output signal is branched by the coupler 17 and down-converted to an intermediate frequency by the down converter 18 based on the local oscillation frequency f L of the local oscillator 15. Thereafter, the output signal digitally converted by the wideband ADC 19 is input to the parameter adjustment unit 20 as a feedback signal y.
  • the transmission circuit 11 configured as described above, digital signal processing is introduced in order to perform highly accurate nonlinear compensation.
  • the DPD 12 is a lookup table type
  • the vector amplitude of the output signal with respect to the amplitude of the input signal x A lookup table in which values are stored is used.
  • the parameter adjustment unit 20 adjusts the parameters of the lookup table, so that highly accurate nonlinear compensation in the transmission circuit 11 is maintained.
  • the DPD 12 is an arithmetic type, highly accurate nonlinear compensation is maintained by adjusting the polynomial of the arithmetic circuit.
  • FIG. 2 is a diagram showing a configuration example of a conventional transmission circuit capable of simultaneous transmission and nonlinear compensation in two frequency bands.
  • the transmission circuit 11A includes two DPDs 12-1 and 12-2, two DACs 13-1 and 13-2, two up-converters 14-1 and 14-2, Local oscillators 15-1 and 15-2, power amplifier 16, coupler 17, two down converters 18-1 and 18-2, two ADCs 19-1 and 19-2, parameter adjustment unit 20, and adder 21 is comprised.
  • input signals x 1 and x 2 at intermediate frequencies corresponding to two frequencies are input to both DPDs 12-1 and 12-2 that are digital predistortion circuits.
  • the distortion compensation signal v 1 output from the DPD 12-1 is converted into an analog signal by the DAC 13-1, and then mixed with the local oscillation frequency f L1 of the local oscillator 15-1 by the up-converter 14-1 to obtain the radio frequency f 1 . Up-converted.
  • the distortion compensation signal v 2 output from the DPD 12-2 is analog-converted by the DAC 13-2, and then mixed with the local oscillation frequency f L2 of the local oscillator 15-2 by the up-converter 14-2. It is up-converted to f 2.
  • the distortion compensation signals v 1 and v 2 up-converted to different radio frequencies f 1 and f 2 are added and synthesized by the adder 21 and then amplified by the power amplifier 16 which is a non-linear circuit.
  • the distortion of the distortion compensation signals v 1 and v 2 is restored due to the non-linearity of the power amplifier 16, and output signals having the same waveforms as the input signals x 1 and x 2 are output.
  • the output signal output from the power amplifier 16 is branched by the coupler 17 and supplied to the down converters 18-1 and 18-2.
  • the output signal is down-converted to an intermediate frequency based on the local oscillation frequency f L1 of the local oscillator 15-1 by the down converter 18-1, digitally converted by the ADC 19-1, and converted into a feedback signal y 1 as a parameter adjustment unit. 20 is input.
  • the output signal is down-converted to an intermediate frequency based on the local oscillation frequency f L2 of the local oscillator 15-2 by the down converter 18-2, digitally converted by the ADC 19-2, and parameter-adjusted as a feedback signal y 2 Input to the unit 20.
  • the parameter adjustment section 20 by using the feedback signals y 1 and the feedback signal y 2, if DPD12-1 and 12-2 is a look-up table type, to adjust the parameters of the respective look-up table, High-precision nonlinear compensation is maintained in the transmission circuit 11A. Note that when the DPDs 12-1 and 12-2 are arithmetic, high-precision nonlinear compensation is maintained by adjusting the polynomial of the arithmetic circuit.
  • the transmission circuit 11A corresponding to two frequencies conventionally needs to include two sets of feedback circuits (down converters 18-1 and 18-2 and ADCs 19-1 and 19-2) for feeding back an output signal. was there.
  • the digital predistorter disclosed in Patent Document 1 is also provided with two ADCs, like the transmission circuit 11A.
  • the present disclosure has been made in view of such a situation, and is intended to enable cost reduction and size reduction.
  • a wireless communication apparatus includes a predetermined number of distortion compensation processing units that perform distortion compensation processing for compensating distortion in a subsequent nonlinear circuit for each of a predetermined number of input signals, and inputs the distortion compensation processing units
  • a distortion compensation processing unit applies an output signal that is amplified and output after a predetermined number of distortion compensation signals, which have been subjected to distortion compensation processing, are up-converted to different frequencies and synthesized.
  • An adjustment unit that adjusts the distortion correction processing applied, and a feedback unit that down-converts an output signal composed of a predetermined number of different frequency components to an intermediate frequency that is smaller than a predetermined number and feeds back to the adjustment unit,
  • all input signals other than the input signal are input together with the input signal to be subjected to distortion compensation processing.
  • the distortion compensation signal output from the distortion compensation processing unit is input to the adjustment unit, which adjusts the frequency of the feedback signal whose signal spectrum is inverted as the output unit down-converts the output signal.
  • An operation method includes a predetermined number of distortion compensation processing units that perform distortion compensation processing for compensating distortion in a subsequent nonlinear circuit for each of a predetermined number of input signals, and the input signals in the distortion compensation processing unit.
  • the distortion compensation processing unit applies the output signal that is amplified and output after up-converting and synthesizing a predetermined number of distortion compensation signals that have been subjected to distortion compensation processing to the input signals.
  • Wireless communication comprising: an adjustment unit that adjusts a distortion correction process to be applied; and a feedback unit that down-converts an output signal composed of a predetermined number of different frequency components to a lower number of intermediate frequencies and feeds back to the adjustment unit
  • An operation method of the apparatus wherein each of a predetermined number of distortion compensation processing units includes an input signal to which a distortion compensation process is applied, and an input thereof.
  • the distortion compensation signal output from the distortion compensation processing unit is input to the adjustment unit, and the adjustment unit performs signal conversion as the output signal is down-converted in the feedback unit.
  • each of a predetermined number of distortion compensation processing units receives an input signal that is a target for which distortion compensation processing is performed, and all input signals other than the input signal.
  • the distortion compensation signal output from the unit is input to the adjustment unit.
  • the frequency component of the feedback signal whose signal spectrum is inverted as the output signal is down-converted is compared with the input signal corresponding to the frequency component, the feedback signal and the input Processing for inverting the signal spectrum of one of the signals is performed.
  • cost reduction and size reduction can be achieved.
  • FIG. 1 It is a block diagram which shows the structural example of a multistage down converter. It is a figure which shows the relationship of the frequency in a multistage down converter. It is a figure explaining intermodulation distortion. It is a figure explaining the characteristic at the time of carrying out the nonlinear compensation of two frequency bands simultaneously.
  • FIG. 3 is a block diagram illustrating a configuration example of the first embodiment of the transmission circuit to which the present technology is applied.
  • the transmission circuit 31 includes two DPDs 32-1 and 32-2, two DACs 33-1 and 33-2, two up-converters 34-1 and 34-2, and two local oscillators 35. -1 and 35-2, an adder 36, a power amplifier 37, a coupler 38, a down converter 39, a local oscillator 40, an ADC 41, and a parameter adjustment unit 42.
  • the DPD 32-1 performs digital signal processing on the input signal x 1 input to the transmission circuit 31 so that the non-linearity is opposite to the non-linearity of the power amplifier 37.
  • a distortion compensation signal v 1 that compensates for the distortion is generated and supplied to the DAC 33-1 and the parameter adjustment unit.
  • the DPD 32-2 performs digital signal processing similar to the DPD 32-1 on the input signal x 2 and supplies the distortion compensation signal v 2 to the DAC 33-2 and the parameter adjustment unit 42.
  • both the input signals x 1 and x 2 are input to the DPDs 32-1 and 32-2, respectively. It will be necessary. This is because cross modulation distortion is generated by the input signals x 1 and x 2 because the power amplifier 37 is common. Therefore, DPD32-1 generates a distortion compensation signal v 1 which compensates for the distortion affected input signal x 2 not only the input signal x 1, DPD32-2 not only the input signal x 2 input signal x A distortion compensation signal v 2 that compensates for the distortion affected by 1 is generated.
  • the DPD 32-1 and 32-2 are configured by a single-chip signal processing circuit (for example, FPGA: Field Programmable Gate Array) that performs two parallel digital signal processing.
  • DAC33-1 provides distortion compensation signal v 1 which is supplied from DPD32-1 into analog, the up-converter 34-1.
  • DAC33-2 supplies a compensation signal v 2 supplied from DPD32-2 into analog, the up-converter 34-2.
  • the up-converter 34-1 multiplies the analog distortion compensation signal v 1 supplied from the DAC 33-1 by the local oscillation signal of the local oscillation frequency f L1 supplied from the local oscillator 35-1, thereby obtaining a distortion compensation signal. v 1 and by up-converting to a radio frequency f 1, and supplies the distortion compensation signal v 1 of the radio frequency f 1 to the adder 36. Similarly, the up-converter 34-2 up-converts the distortion compensation signal v 2 to the radio frequency f 2 and supplies it to the adder 36.
  • the local oscillator 35-1 generates a local oscillation signal having a local oscillation frequency f L1 such that the frequency of the radio signal output from the transmission circuit 31 is the radio frequency f 1 and supplies the local oscillation signal to the up-converter 34-1.
  • local oscillator 35-2 generates a local oscillation signal having local oscillation frequency f L2 and supplies it to up-converter 34-2.
  • the adder 36 by adding a distortion compensation signal v 1 of the radio frequency f 1 supplied from the up converter 34-1, and the distortion compensation signal v 2 of the radio frequency f 2 supplied from the up converter 34-2 And the synthesized output signal is supplied to the power amplifier 37.
  • the power amplifier 37 amplifies the output signal synthesized in the adder 36. At this time, due to the nonlinearity of the power amplifier 37, the distortion of the distortion compensation signals v 1 and v 2 applied by the DPD 32-1 and 32-2 is restored. As a result, an output signal obtained by synthesizing a waveform similar to the input signal x 1 centered on the radio frequency f 1 and a waveform similar to the input signal x 2 centered on the radio frequency f 2 is output from the power amplifier 37. Is output.
  • the coupler 38 outputs the output signal output from the power amplifier 37 to a circuit (not shown) subsequent to the transmission circuit 31 and branches the output signal as a feedback signal y (f 1 , f 2 ). This is supplied to the down converter 39.
  • the down-converter 39 down-converts the feedback signal y (f 1 , f 2 ) fed back from the power amplifier 37 to the intermediate frequency f IF based on the local oscillation frequency f LO supplied from the local oscillator 40.
  • y (f IF ) is generated and supplied to the ADC 41.
  • the local oscillator 40 generates a local oscillation signal having a local oscillation frequency f LO and supplies it to the down converter 39.
  • the feedback signals y (f 1 , f 2 ) in two frequency bands centered on the radio frequencies f 1 and f 2 are converted into the intermediate frequency f IF. Is converted to a feedback signal y (f IF ) in the same frequency band centering on.
  • the ADC 41 digitally converts the feedback signal y (f IF ) supplied from the down converter 39 and supplies it to the parameter adjustment unit 42.
  • the parameter adjustment unit 42 uses the feedback signal y (f IF ) as information for correcting the parameters of the lookup tables of the DPDs 32-1 and 32-2. That is, the parameter adjustment unit 42 compares the signal spectrum of the frequency component corresponding to the input signal x 1 included in the feedback signal y (f IF ) with the signal spectrum of the input signal x 1 so that they match. , DPD32-1 lookup table parameters are corrected.
  • the parameter adjustment unit 42 has the signal spectrum of the input signal x 1 because the signal spectrum of the frequency component corresponding to the input signal x 1 included in the feedback signal y (f IF ) is inverted. A process of inverting the spectrum is performed for comparison.
  • the parameter adjustment unit 42 performs processing so that the signal spectrum of the frequency component corresponding to the input signal x 2 included in the feedback signal y (f IF ) matches the signal spectrum of the input signal x 2 ,
  • the DPD 32-2 lookup table parameters are corrected.
  • the parameter adjustment unit 42 can correct the distortion in the power amplifier 37 by correcting the parameters of the lookup tables of the DPDs 32-1 and 32-2.
  • DPD 32-1 and 32-2 are arithmetic types
  • parameter adjustment unit 42 can compensate for distortion in power amplifier 37 by adjusting the polynomial of the arithmetic circuit.
  • the transmission circuit 31 configured as described above has a different feedback circuit compared to the conventional transmission circuit 11A described with reference to FIG. 2, and includes only one set of the down converter 39 and the ADC 41. Configured.
  • a local oscillation frequency f LO of the local oscillator 40 by setting the center of the radio frequency f 1 and the radio frequency f 2, the feedback signal y (f 1, f 2)
  • the feedback signal y (f IF ) in the same frequency band centered on the intermediate frequency f IF can be converted.
  • FIG. 4 is a block diagram showing a configuration example of the parameter adjustment unit 42 of FIG.
  • the parameter adjustment unit 42 includes a time adjustment unit 51, two PA (Power Amplifier) models 52-1 and 52-2, a modeling unit 53, and an inverse characteristic modeling unit 54.
  • the parameter adjustment unit 42 includes a time adjustment unit 51, two PA (Power Amplifier) models 52-1 and 52-2, a modeling unit 53, and an inverse characteristic modeling unit 54.
  • the time adjustment unit 51 is supplied with the distortion compensation signals v 1 and v 2 from the DPDs 32-1 and 32-2, and is also supplied with the feedback signal y from the down converter 39, and the distortion compensation signal v 1 for the feedback signal y and v to correct the deviation of the second time.
  • This time lag is caused in the feedback circuit until the distortion compensation signals v 1 and v 2 output from the DPDs 32-1 and 32-2 are input to the parameter adjustment unit 42 as the feedback signal y via the power amplifier 37. Occurs and varies depending on the radio frequency.
  • the time adjustment unit 51 supplies the distortion compensation signals v 1 and v 2 in which the time deviation with respect to the feedback signal y is corrected to the modeling unit 53.
  • PA model 52-1 is a model representing the input-output nonlinear characteristics of the power amplifier 37 to the input signal x 1
  • PA model 52-2 is a model representing the input-output nonlinear characteristics of the power amplifier 37 to the input signal x 2 is there. Both input signals x 1 and x 2 are input to PA models 52-1 and 52-2, respectively.
  • the PA models 52-1 and 52-2 are expressed by the following equation (1), for example.
  • the PA model 52-1 is determined by the polynomial coefficient set ⁇ a q, r, m ⁇ of y m1 (n) in the equation (1), and these coefficients are used as a model parameter as a coefficient vector A 1 .
  • the PA model 52-2 is determined by the coefficient set ⁇ b q, r, m ⁇ of the polynomial of y m2 (n) in the equation (1), and these coefficients are used as a model parameter as a coefficient vector A 2. Use.
  • the output y m1 from the PA model 52-1 and the output y m2 from the PA model 52-2 are expressed by the following equation (2) using the input signals x 1 and x 2 as inputs, and this value is It can be considered as the output of the power amplifier 37 in a configuration in which the DPD 32-1 and 32-2 are not provided.
  • the modeling unit 53 compares the feedback signal y with the distortion compensation signals v 1 and v 2 corrected for the time deviation supplied from the time adjustment unit 51. At this time, if the modeling unit 53 separates the output y 1 and the output y 2 from the feedback signal y and the spectrum obtained by inverting the spectrum of the output y 1 is a conjugate complex output y * 1 represented by the conjugate complex number, the modeling unit 53 provides feedback.
  • the signal y is expressed by the following equation (3).
  • X 1 and X 2 are equivalent to Equation (2), but are vectors whose inputs are distortion compensation signals v 1 and v 2 .
  • the modeling unit 53 uses the relationship of the expression (3) between the feedback signal y and the distortion compensation signals v 1 and v 2 whose time deviation is corrected, and uses the coefficient vector A 1 and A 2 is estimated by the method of least squares. As a result, the modeling unit 53 can use the coefficient vectors A 1 and A 2 to determine the coefficients of the PA models 52-1 and 52-2. However, since the output y 1 is spectrum-inverted, the obtained coefficient vector becomes the conjugate complex number A * of A. Therefore, taking this complex conjugate makes the coefficient vector A. The modeling unit 53 can separate the output y 1 and the output y 2 from the feedback signal y according to the following equations (4) and (5).
  • the inverse characteristic modeling unit 54 obtains an inverse polynomial of the polynomial shown in the above equation (1), and the inverse polynomial is obtained as the DPD 32-1 and 32- A polynomial of 2 is assumed.
  • the parameter adjustment unit 42 is configured, and separates the output y 1 and the output y 2 corresponding to the input signals x 1 and x 2 from the feedback signal y (f IF ), respectively, so that the inverse characteristic of the power amplifier 37 is obtained.
  • DPD 32-1 and 32-2 can be adjusted so that
  • FIG. 5 shows the frequency relationship in the feedback circuit of the transmission circuit 31.
  • FIG. 5A shows a signal spectrum of the feedback signal y (f 1 , f 2 ) input to the down converter 39
  • FIG. 5B shows a feedback signal down-converted by the down converter 39.
  • the signal spectrum of y (f IF ) is shown.
  • the feedback signal y (f 1 , f 2 ) is represented by a signal spectrum centered on each of the radio frequency f 1 and the radio frequency f 2 .
  • the parameter adjustment section 42 a radio frequency f 1 centered signal spectrum, i.e., the signal spectrum of a frequency component corresponding to the input signals x 1, directly, the compared with the input signal x 1 error I can't ask for it.
  • the parameter adjustment section 42 performs a process of inverting the signal spectrum of the input signal x 1, the signal spectrum of the input signal x 1 after the inverted input signal x 1 that is included in the feedback signal y (f IF) It is necessary to compare the signal spectrum of the frequency component corresponding to.
  • the parameter adjustment unit 42 may invert the signal spectrum of the frequency component corresponding to the input signal x 1 included in the feedback signal y (f IF ) and compare it with the signal spectrum of the input signal x 1 as it is. Good. That is, the parameter adjustment unit 42 may perform a process of inverting any one of the signal spectra for the input signal x 1 .
  • a signal spectrum centered on a radio frequency f 2 higher than the local oscillation frequency f LO is converted into an intermediate frequency f IF without being inverted as it is. Therefore, when the parameter adjustment unit 42 obtains an error by comparing the feedback signal y (f IF ) with the input signal x 2 , it is not necessary to perform a process of inverting the signal spectrum of the input signal x 2 .
  • the transmission circuit 31 corresponding to the two frequencies includes only one set of the down converter 39 and the ADC 41, it is possible to suppress the occurrence of intermodulation distortion, as in the conventional case.
  • FIG. 6 shows a spectrum of a signal having a lower frequency (1.75 GHz) when the transmission circuit 31 transmits two signals of a signal having a frequency of 1.75 GHz and a signal having a frequency of 2.75 GHz.
  • FIG. 6A shows a signal spectrum of an output signal output from a transmission apparatus having no DPD.
  • FIG. 6B shows the signal spectrum of the output signal in the conventional configuration including the transmission circuit 11A as shown in FIG. 2, that is, a plurality of sets of feedback circuits proportional to the corresponding frequency band.
  • FIG. 6C a signal spectrum in the configuration of the transmission circuit 31 is shown. Note that the same effect as the signal with the lower frequency is observed for the signal with the higher frequency (2.75 GHz), so the spectrum of the signal with the higher frequency is omitted, and the signal with the lower frequency is displayed.
  • FIG. 6C shows a signal spectrum in the configuration of the transmission circuit 31 . Note that the same effect as the signal with the lower frequency is observed for the signal with the higher frequency (2.75
  • the spread of the waveform width of the signal spectrum is suppressed, and the occurrence of intermodulation distortion is suppressed in both configurations.
  • the signal spectra of B of FIG. 6 and C of FIG. 6 have substantially the same waveform, and it can be seen that the transmission circuit 31 has substantially the same performance as the transmission circuit 11A having the conventional configuration.
  • the performance of the transmission circuit 31 having a set of feedback circuits does not deteriorate even when compared with the conventional configuration transmission circuit 11A. Therefore, the transmission circuit 31 can realize a function of suppressing the occurrence of intermodulation distortion as in the conventional case at a lower cost and a smaller size by reducing the configuration of the feedback circuit.
  • FIG. 7 is a block diagram illustrating a configuration example of the second embodiment of the transmission circuit to which the present technology is applied.
  • the transmission circuit 31A of FIG. 7 has a configuration common to the transmission circuit 31 of FIG. 3 in that it includes an adder 36, a power amplifier 37, a coupler 38, and an ADC 41.
  • the transmission circuit 31A includes N DPDs 32-1 to 32-N, N DACs 33-1 to 33-N, N up-converters 34-1 to 34-N, and N local oscillators 35-1. 3 to 35-N and a parameter adjustment unit 42A, and a multi-stage down converter 43 is provided in place of the down converter 39 and the local oscillator 40 of FIG.
  • the transmission circuit 31A is configured to be capable of simultaneous transmission and non-linear compensation in N frequency bands, and includes N DPDs 32-1 to 32-N, N DACs 33-1 to 33-N, N
  • the N up-converters 34-1 to 34-N and the N local oscillators 35-1 to 35-N correspond to the N series of input signals x 1 to x N.
  • the DPDs 32-1 to 32-N are configured by a one-chip signal processing circuit that performs N parallel digital signal processing.
  • these N-sequence output signals are combined by the adder 36 and then input to the power amplifier 37.
  • the output signal output from the power amplifier 37 is branched by the coupler 38, and the feedback signal y (F 1 , f 2 , f 3 ,... F N ) are input to the multistage down converter 43.
  • the multistage down-converter 43 performs down-conversion on the feedback signal y (f 1 , f 2 , f 3 ,... F N ) in a plurality of stages as described with reference to FIGS.
  • the feedback signal y (N) down-converted to the intermediate frequency f IF is generated and supplied to the ADC 41.
  • the parameter adjustment unit 42A like the parameter adjustment unit 42 of FIG. 3, is based on the feedback signals y (f 1 , f 2 , f 3 ,... F N ) and the DPDs 32-1 to 32-N. Correct the parameters or adjust the polynomial of the arithmetic circuit.
  • the parameter adjustment unit 42A has N PA models 52 (see FIG. 4) corresponding to the DPDs 32-1 to 32-N.
  • FIG. 8 is a block diagram showing a configuration example of the multi-stage down converter 43.
  • N-1 down converters 39-1 to 39- (N-1) are connected in series, and the down converters 39-1 to 39- (N-1) are connected.
  • N-1 local oscillators 40-1 to 40- (N-1) are provided for each.
  • the down converter 39-1 down-converts the feedback signal y (f 1 , f 2 , f 3 ,... F N ) based on the local oscillation frequency f LO (1) supplied from the local oscillator 40-1. Generated feedback signal y (1) .
  • the down converter 39-2 generates a feedback signal y (2) obtained by down-converting the feedback signal y (1) based on the local oscillation frequency f LO (2) supplied from the local oscillator 40-2.
  • the down converter 39-3 generates a feedback signal y (3) obtained by down-converting the feedback signal y (2) based on the local oscillation frequency f LO (3) supplied from the local oscillator 40-3.
  • the down converter 39- (N-1) is supplied from the local oscillator 40- (N-1).
  • a feedback signal y (N) obtained by down-converting the feedback signal y (N-1 ) is generated.
  • the local oscillation frequency f LO (N-1) of the local oscillator 40- (N-1) is equal to the intermediate frequency ⁇ (f N-1 -f N-2 ) / 2 of the feedback signal y (N-2).
  • the parameter adjustment unit 42A needs to perform comparison in consideration of the inversion of the signal spectrum. There is.
  • FIG. 9 is a diagram showing a frequency relationship in the multi-stage down converter 43.
  • the radio frequency f 1 to f N corresponding to the respective input signals x 1 to x N
  • the radio frequency f 1 is the smallest increases in the order from the radio frequency f 1 to a radio frequency f N
  • FIG. 9 shows an example in which the frequencies are retracted in ascending order of the radio frequencies f 1 to f N.
  • the frequency components of 1 and the radio frequency f 2 are converted to the same intermediate frequency ⁇ (f 2 ⁇ f 1 ) / 2 ⁇ by degeneration.
  • the feedback signal y (1) output from the down converter 39-1 is as shown in the second stage from the top in FIG.
  • the frequency components of the radio frequencies f 1 to f 3 are converted into the same intermediate frequency ⁇ (f 3 ⁇ f 2 ) / 2 ⁇ by being reduced.
  • the feedback signal y (2) output from the down converter 39-2 becomes as shown in the third stage from the top in FIG.
  • the frequency components of the radio frequencies f 1 to f N corresponding to the input signals x 1 to x N are shown in the fourth row from the top in FIG. 9 by performing the down-conversion based on f N-2 ) / 2 ⁇ .
  • results of such down-conversion is performed in a multistage downconverter 43, the feedback signal y (N), if the number of systems N of the input signal x is an even number, the radio frequency f 1, f 3, ⁇ f N-1 The signal spectrum of radio frequencies f 2 , f 4 ,... F N is output as it is. Therefore, when the number N of systems of the input signal x is an even number, the parameter adjustment unit 42A performs feedback after inverting the signal spectrum representing the input signals x 1 , x 3 ,... X N-1 in the intermediate frequency band. It is necessary to compare with the signal y (N) . In the case strains speed N of the input signal x is an even number, the input signal x 2, x 4, for ⁇ ⁇ ⁇ x N is not necessary to perform such a reversal.
  • the parameter adjusting unit 42A when the number of systems N of the input signal x is an odd number, the input signal x 2, x 4, the ⁇ ⁇ ⁇ x N after inverting the signal spectrum expressed in an intermediate frequency band, the feedback signal y It is necessary to compare with (N) .
  • the number N of systems of the input signal x is an odd number, such inversion is not necessary for the input signals x 1 , x 3 ,... X N ⁇ 1 .
  • the parameter adjustment unit 42A determines the input signal to be inverted according to the number N of systems of the input signal x, and the frequency components of the signal spectrum that are inverted as the multi-stage down converter 43 performs the down conversion. Performs a process of inverting the input signal corresponding to the frequency component, and then compares it with the feedback signal y (N) .
  • the transmission circuit 31A can convert the output signals of a plurality of frequency bands into a single intermediate frequency
  • the feedback signal y (N) output from the multistage downconverter 43 is converted to a single ADC 41.
  • the processing can be performed by the single ADC 41, the number of ADCs to be used can be reduced as compared with the conventional transmission circuit, so that the circuit is simplified, the power consumption is reduced, and the size is reduced. And cost reduction.
  • the input signal x 1 the input signal x 1 not only distortion d (1, 1) is generated, even distortion d (1, 2) is generated by the input signal x 2 To do.
  • the intermodulation distortion due to the mutual influence occurs in the input signal x 1 and the input signal x 2 .
  • the transmission circuit 31 of FIG. 3 to which the present technology is applied is configured such that the input signal x 2 is input to the DPD 32-1 together with the input signal x 1 to which the DPD 32-1 performs digital signal processing. Is done.
  • the DPD32-2, DPD32-2 together with the input signal x 2 of interest subjected to digital signal processing, an input signal x 1 is also input.
  • the DPD 32-1 not only compensates for the distortion d (1, 1) using the input signal x 1 , but also performs digital signal processing for compensating for the distortion d (1, 2) using the input signal x 2.
  • the distortion compensation signal v 1 that compensates for the distortion d (1,1) and the distortion d (1,2) can be generated.
  • DPD32-2 not only compensate for distortion d (2, 2) using the input signal x 2, the digital signal processing for compensating for distortion d (2,1) by using the input signal x 1
  • the distortion compensation signal v 2 in which the distortion d (2,2) and the distortion d (2,1) are compensated can be generated.
  • each of the DPDs 32-1 to 32-N only receives one of the input signals x 1 to x N to be subjected to digital signal processing. However, all the input signals x 1 to x N are input.
  • the transmission circuit 31 and the transmission circuit 31A can generate the distortion compensation signal v that compensates for the intermodulation distortion generated due to the influence of the plurality of input signals x, so that distortion compensation can be performed with higher accuracy. it can.
  • the transmission circuit 31 and the transmission circuit 31A can reliably restore the distortion of the distortion compensation signal v by the up-conversion by the up-converter 34, and output an output signal having the same waveform as each input signal x. it can.
  • the frequency band for transmitting the input signal x 1 is 10 MHz
  • the frequency band for transmitting the input signal x 2 is 20 MHz
  • the simulation results of the power spectral density are shown.
  • FIG. 11A shows a configuration of the transmission circuit 31, that is, a configuration in which feedback is performed such that the parameter adjustment unit 42 adjusts parameters using the feedback signal y down-converted to one intermediate frequency f IF by the down converter 39.
  • FIG. The simulation result of the power spectral density in (Spectra-Folding Feed Back) is shown.
  • FIG. 11C shows a simulation result when the amplitude-phase characteristic of the PA model is changed by 10%.
  • FIG. 11B and FIG. 11C in a configuration in which feedback is not performed, if the characteristics of the PA model are changed, distortion occurs in the waveform of the power spectral density.
  • the transmission circuit 31 employs a configuration in which feedback is performed as described above, so that when the two frequency bands are nonlinearly compensated simultaneously, the waveform of the power spectral density It is possible to suppress the occurrence of distortion. That is, the transmission circuit 31 to which the present technology is applied can perform more accurate distortion compensation even if nonlinear compensation is simultaneously performed for two frequency bands.
  • 31 and 31A transmitter circuit 32 DPD, 33 DAC, 34 upconverter, 35 local oscillator, 36 adder, 37 power amplifier, 38 coupler, 39 downconverter, 40 local oscillator, 41 ADC, 42 and 42A parameter adjustment unit, 43 Multi-stage down converter, 51 time adjustment section, 52-1 and 52-2 PA model, 53 modeling section, 54 inverse characteristic modeling section

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
  • Transmitters (AREA)

Abstract

La présente invention concerne un dispositif de communication sans fil qui permet une réduction de coût et de taille, ainsi qu'un procédé de fonctionnement. Un nombre prédéterminé de signaux de compensation de déformation obtenus en soumettant chacun d'un nombre prédéterminé de signaux d'entrée à un processus de compensation de déformation qui compense la déformation dans un circuit non linéaire aval sont convertis à la hausse à des fréquences mutuellement différentes, synthétisés, puis amplifiés et délivrés en tant que signaux de sortie. Sur la base de ces signaux de sortie, une unité de réglage pour régler le processus de compensation de déformation exécuté sur les signaux d'entrée effectue un processus destiné à inverser le spectre de signal des signaux d'entrée ou de signaux de rétroaction lorsque le spectre du signal est comparé aux signaux d'entrée qui correspondent aux composantes de fréquence des signaux de rétroaction pour lesquels les spectres de signal sont inversés, conjointement avec la conversion vers le bas des signaux de sortie dans une unité de rétroaction, le processus étant effectué relativement aux composantes de fréquence. La présente technique peut être utilisée, par exemple, dans un dispositif de communication sans fil doté d'un processus de compensation de déformation.
PCT/JP2016/053791 2015-02-09 2016-02-09 Dispositif de communication sans fil et mode de fonctionnement WO2016129590A1 (fr)

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Cited By (1)

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JP2019201361A (ja) * 2018-05-17 2019-11-21 富士通株式会社 歪補償装置および歪補償方法

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JP2006119148A (ja) * 2005-12-05 2006-05-11 Furuno Electric Co Ltd 信号処理方法、信号処理装置
WO2013084778A1 (fr) * 2011-12-09 2013-06-13 株式会社エヌ・ティ・ティ・ドコモ Précorrecteur et procédé de commande de précorrecteur
US8536943B2 (en) * 2012-02-03 2013-09-17 Telefonaktiebolaget Lm Ericsson (Publ) Selective narrowband feedback for a digital predistorter
JP2015005901A (ja) * 2013-06-21 2015-01-08 株式会社Ｎｔｔドコモ プリディストータ、プリディストータの制御方法

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JP5861521B2 (ja) * 2012-03-19 2016-02-16 富士通株式会社 送信装置及びルックアップテーブルの更新方法
JP2015099972A (ja) * 2013-11-18 2015-05-28 三菱電機株式会社 送信機モジュール

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JP2006119148A (ja) * 2005-12-05 2006-05-11 Furuno Electric Co Ltd 信号処理方法、信号処理装置
WO2013084778A1 (fr) * 2011-12-09 2013-06-13 株式会社エヌ・ティ・ティ・ドコモ Précorrecteur et procédé de commande de précorrecteur
US8536943B2 (en) * 2012-02-03 2013-09-17 Telefonaktiebolaget Lm Ericsson (Publ) Selective narrowband feedback for a digital predistorter
JP2015005901A (ja) * 2013-06-21 2015-01-08 株式会社Ｎｔｔドコモ プリディストータ、プリディストータの制御方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019201361A (ja) * 2018-05-17 2019-11-21 富士通株式会社 歪補償装置および歪補償方法

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