JP4043824B2 - Nonlinear distortion compensation apparatus and nonlinear distortion compensation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonlinear distortion compensator that removes a nonlinear component generated in a radio unit used in a mobile communication device or the like.
[0002]
[Prior art]
Conventionally, as a non-linear distortion compensator for removing a non-linear component generated in a radio unit used in this type of mobile communication device or the like, the one described in JP-A-11-177470 has been known.
With reference to FIG. 4, the configuration of such a conventional nonlinear distortion compensator will be described. The nonlinear distortion compensation apparatus shown in FIG. 4 includes a power calculation unit 402 that calculates a power value of a transmission signal from an input orthogonal baseband signal 401, and a first reference table 403 that stores nonlinear distortion compensation coefficients of the orthogonal modulation unit 408. A second reference table 404 storing nonlinear distortion compensation coefficients of the amplification unit 409, a compensation coefficient calculation unit 405 for obtaining a nonlinear distortion compensation coefficient of the modulation signal 410 from the first and second reference tables 403, 404, and A distortion compensation calculation unit 406 that multiplies the non-linear distortion compensation coefficient of the radio unit 411 stored in the first and second reference tables 403 and 404 and the baseband signal 401, an orthogonal modulation unit 408, and a power amplification unit 409. The wireless unit 411 is configured.
[0003]
Next, the operation of the conventional nonlinear distortion compensator configured as described above will be described. The compensation coefficient calculation unit 405 determines the first and second known nonlinear distortion compensation amounts of the quadrature modulation unit 408 and the power amplification unit 409 constituting the radio unit 410 by the power calculation unit 402 according to the amplitude value of the output baseband signal. The non-linear distortion compensation amount of the entire wireless unit 411 is calculated from the reference tables 403 and 404. A distortion compensation calculation unit 406 multiplies the orthogonal baseband signal 401 by a complex product with the nonlinear distortion compensation amount output from the compensation coefficient calculation unit 405, thereby adding a nonlinear distortion compensation amount to the input signal of the wireless unit 411. In the output signal of the wireless unit 411 having nonlinear distortion characteristics, a signal having no distortion component is obtained, and nonlinear distortion compensation can be realized.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional nonlinear distortion compensation device, since the distortion compensation amount cannot be changed in accordance with the variation of the distortion compensation amount of the radio unit due to external variation factors such as the power supply voltage and the ambient temperature, the optimum nonlinear distortion compensation There was a problem that it was difficult to do.
The present invention has been made in order to solve the above-described conventional problems, and without using a feedback circuit of output power, it is possible to reduce the distortion compensation amount of the radio unit due to external fluctuation factors such as power supply voltage and ambient temperature. The present invention provides a non-linear distortion compensator that can be used.
[0005]
[Means for Solving the Problems]
The nonlinear distortion compensator of the present invention includes distortion compensation basic data which is one distortion compensation data among a plurality of distortion compensation data of a power amplification unit corresponding to a variation in adaptive information indicating a variation in operating environment acquired in advance, A coefficient update unit that generates a distortion compensation data corresponding to the adaptation information by multiplying a variation approximation formula that approximates a variation of the distortion compensation basic data with respect to the adaptation information, and a distortion compensation generated by the coefficient update unit A distortion compensation calculation unit that compensates nonlinear distortion of the output IQ signal using data, an orthogonal modulation unit that orthogonally modulates the output IQ signal subjected to nonlinear distortion compensation by the distortion compensation calculation unit, and orthogonally modulated by the orthogonal modulation unit And a power amplifying unit for amplifying the modulation signal. With this configuration, it is possible to perform distortion compensation corresponding to fluctuations in adaptive information indicating fluctuations in the operating environment by controlling the coefficients of distortion compensation data sequentially without switching distortion compensation tables. Complexity can be saved.
[0006]
The nonlinear distortion compensator of the present invention includes one in which the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to a power supply voltage of the power amplifier. With this configuration, it is possible to perform distortion compensation corresponding to power supply voltage fluctuations by controlling the coefficient of distortion compensation data sequentially without switching distortion compensation tables, and to reduce the complexity of table switching control. .
[0007]
The nonlinear distortion compensator according to the present invention includes an apparatus in which the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to an ambient temperature of the power amplifier. With this configuration, adaptive information can be controlled as temperature fluctuations, and distortion compensation corresponding to temperature fluctuations can be performed by sequentially updating the coefficient of distortion compensation data.
[0008]
The nonlinear distortion compensator of the present invention includes one in which the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to a power supply voltage and an ambient temperature of the power amplifier. With this configuration, it is possible to perform distortion compensation corresponding to power supply voltage fluctuations and temperature fluctuations by sequentially updating distortion compensation data coefficients.
[0009]
In the nonlinear distortion compensator according to the present invention, the power amplifying unit is a variable power amplifying unit capable of adjusting an output power, and further, transmission power for controlling the output power of the variable power amplifying unit corresponding to the adaptive information Including those provided with control means. With this configuration, the variable power amplifying unit is controlled by the gain control signal from the transmission power control means against the variation of the distortion compensation amount due to the fluctuation of the operating environment of the radio unit without using the output power feedback circuit. The nonlinear distortion compensation amount can be held.
[0010]
The nonlinear distortion compensator of the present invention further includes an IQ amplitude adjusting unit that adjusts the amplitude of the output IQ signal that has been nonlinear distortion compensated by the distortion compensation calculation unit, and the output power control unit corresponds to the adaptive information. And controlling the IQ amplitude adjusting unit. With this configuration, the output IQ amplitude is adjusted by digital processing in response to the distortion compensation amount variation due to the operating environment variation of the wireless unit without using the feedback circuit of the output power in the wireless unit, and the nonlinear distortion compensation amount is reduced. Can be held.
[0011]
The nonlinear distortion compensation method of the present invention includes distortion compensation basic data which is one distortion compensation data among a plurality of distortion compensation data of a power amplifying unit corresponding to a variation in adaptive information indicating a variation in operating environment acquired in advance. A coefficient updating step of generating distortion compensation data according to the adaptation information by multiplying the variation information by the variation approximation formula approximating the variation of the distortion compensation basic data with respect to the adaptation information;
A distortion compensation calculation step for nonlinear distortion compensation of the output IQ signal using the distortion compensation data generated in the coefficient update step; an orthogonal modulation step for orthogonally modulating the output IQ signal nonlinearly compensated for in the distortion compensation calculation step; And a power amplification step of amplifying the modulation signal orthogonally modulated in the orthogonal modulation step by the power amplification unit. With this configuration, it is possible to perform distortion compensation corresponding to fluctuations in adaptive information indicating fluctuations in the operating environment by controlling the coefficients of distortion compensation data sequentially without switching distortion compensation tables. Complexity can be saved.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, first to third embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
First, the configuration of the nonlinear distortion compensator according to the first embodiment of the present invention will be described with reference to FIG. The nonlinear distortion compensation apparatus shown in FIG. 1 includes a power calculation unit 104, a distortion compensation data table 106, a distortion compensation calculation unit 105, D / A conversion units 107 and 108, and whether the adaptive information is a power supply voltage 110 or a temperature. 111, a baseband unit 101 having a table switching control unit 109 that switches and selects distortion compensation data stored in the distortion compensation data table 106, an orthogonal modulation unit 113, a power amplification unit 114, and an antenna 115. And a wireless unit 112 having Note that the baseband unit 101 and the wireless unit 112 constitute a part of the wireless transmission / reception apparatus.
[0022]
Next, the operation of the nonlinear distortion compensator according to the first embodiment of the present invention will be described with reference to FIG. First, a plurality of inverse distortion characteristics corresponding to the adaptation information (power supply voltage 110) of the power amplification unit 114 is acquired in advance, and stored as distortion compensation data in the distortion compensation data table 106, corresponding to each adaptation information. Then, the distortion compensation data stored in the distortion compensation data table 106 is switched and selected under the control of the table switching control unit 109, and the selected distortion compensation data and the input IQ signals 102 and 103 are converted into nonlinear distortion. Compensation calculation unit (also referred to as distortion compensation calculation unit) 105 calculates and compensates for distortion, and the distortion-compensated IQ signal is amplified by power amplification unit 114 via D / A conversion units 107 and 108 and quadrature modulation unit 113. The
[0023]
As described above, according to the present embodiment, the distortion compensation data table 106 is switched according to the power supply voltage 110 that is the adaptation information and the appropriate distortion compensation data is used, regardless of the fluctuation of the power supply voltage. As a result, an effect that nonlinear distortion can be reduced is obtained.
[0024]
In addition, the adaptive distortion is set to temperature 111, the reverse distortion characteristics of the power amplifier 113 are acquired in advance, and the distortion compensation data table is switched according to the temperature fluctuation, thereby reducing nonlinear distortion regardless of the temperature fluctuation. The effect that it can do is acquired.
[0025]
Further, the adaptive information is set to the power supply voltage 110 and the temperature fluctuation 111, the reverse distortion characteristics of the power amplifying unit 113 are acquired in advance, and the distortion compensation data table is switched according to each adaptive information, so that the fluctuation of the power supply voltage and the temperature are changed. Regardless of the fluctuation of the non-linearity, it is possible to reduce the nonlinear distortion.
[0026]
(Second Embodiment)
Next, with reference to FIG. 2, illustrating the configuration of a nonlinear distortion compensating apparatus according to the second embodiment of the present invention. The nonlinear distortion compensator in the present embodiment shown in FIG. 2 is different from that in the first embodiment shown in FIG. 1 in one distortion compensation basic data (one distortion compensation data among a plurality of distortion compensation data). Data) (basic data) 207 and variation approximation expression 208 approximating the variation of distortion compensation basic data 207 with respect to adaptive information (power supply voltage 212) are multiplied by coefficient updating unit 206 to generate new distortion compensation data. The difference is that the compensation calculation unit 205 calculates the IQ signals 202 and 203. Other components are the same as those in the first embodiment.
[0027]
As described above, according to the present embodiment, distortion compensation by sequential control is possible in accordance with the power supply voltage 212. Therefore, the complexity of table switching control is eliminated, and even if the power supply voltage fluctuates continuously. An effect is obtained that nonlinear distortion can be reduced while maintaining a constant distortion compensation effect.
[0028]
Further, the adaptive information is set to the temperature 211, the fluctuation approximate expression 208 is acquired in advance from the reverse distortion characteristic of the power amplification unit 215, and the distortion compensation data is generated by the timed control according to the temperature 211, thereby switching the table. It is possible to reduce the non-linear distortion while maintaining a constant distortion compensation effect continuously even if the temperature varies, without the complexity of the control.
[0029]
Further, the adaptive information is set to the power supply voltage 212 and the temperature 211, and the fluctuation approximation expression 208 is obtained in advance from the reverse distortion characteristics of the power amplifier 215, and the distortion compensation data is obtained by time-dependent control according to the power supply voltage 212 and the temperature 211. Thus, it is possible to reduce the complexity of the table switching control and reduce the nonlinear distortion while always maintaining a constant effect regardless of the power supply voltage fluctuation and the temperature fluctuation.
[0030]
(Third embodiment)
Next, with reference to FIG. 3, the structure of the nonlinear distortion compensation apparatus in the 3rd Embodiment of this invention is demonstrated. The non-linear distortion compensation apparatus in the present embodiment shown in FIG. 3 is different from those in the first and second embodiments shown in FIGS. 1 and 2 in that a variable power amplification unit capable of adjusting output power as output power control means. 314 and transmission power control means 316 that outputs a gain control signal are provided, and control is performed so as to keep the output power constant. Other components are the same as those in the first and second embodiments.
[0031]
As described above, according to the present embodiment, with respect to fluctuations in output power corresponding to each adaptive information (power supply voltage 310, temperature 311), the amount of fluctuation in output power is previously stored in transmission power control means 316 as data. The variable power amplifying unit 314 is controlled by the output power fluctuation amount corresponding to each adaptive information. By controlling the variable power amplifying unit 314 as described above, the output power can be kept constant without using a feedback circuit including the output power detecting unit. Therefore, the processing by the control unit can be reduced, and the distortion compensation amount that can correspond to the distortion compensation of the wireless unit 312 that varies with each adaptive information can be selected from the distortion compensation data or the distortion compensation basic data, thereby reducing the power supply voltage variation and the temperature variation. Regardless, there is an effect that the output power can be kept constant while reducing the non-linear distortion.
[0032]
Further, the IQ amplitude adjusting unit 317 is used as the output power control function, and the output power fluctuation amount corresponding to the output power fluctuation due to the adaptation information (power supply voltage 310, temperature 311) is stored in advance in the transmission power control means 316 as each data, The IQ amplitude adjustment unit 317 is controlled by the information. As a result, regardless of the power supply voltage fluctuation and the temperature fluctuation, the output power can be held constant without reducing the non-linear distortion and without adding a control circuit to the radio unit 312.
[0034]
Further, in addition to each adaptive information (power supply voltage 310, temperature 311), the distortion compensation amount for each frequency to be used is stored in advance in a control unit (not shown) as data, and is selectively controlled by the transmission power control means 316. As a result, it is possible to reduce the nonlinear distortion regardless of the frequency used.
[0035]
Further, by controlling the control unit, the temperature of the variable power amplifying unit 314 is controlled by operating the variable power amplifying unit 314 in a no-input power state for a predetermined time before transmitting the transmission slot of the TDMA operation by the transmitting / receiving device. Keep it close to steady use. Thereby, the rapid temperature rise of the variable power amplifier 314 in the transmission slot can be reduced, and the temperature error between the temperature of the variable power amplifier 314 and the temperature detected by the temperature detector can be reduced. As a result, the optimum distortion compensation table or distortion compensation coefficient corresponding to the adaptive information can be selected even during TDMA operation, and the effect of reducing nonlinear distortion can be obtained.
[0041]
【The invention's effect】
The nonlinear distortion compensator according to the present invention is configured as described above. In particular, the adaptive compensation information includes distortion compensation amount data corresponding to the variation of the distortion compensation amount of the radio unit due to the variation of the operating environment such as the power supply voltage and the ambient temperature. By storing the distortion compensation table corresponding to each adaptive information in advance or controlling the distortion compensation coefficient and output power, the nonlinear distortion of the power amplification unit can be achieved without using the output power feedback circuit. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a nonlinear distortion compensation apparatus in a first embodiment of the present invention;
FIG. 2 is a block diagram showing a nonlinear distortion compensation apparatus according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing a nonlinear distortion compensator according to a third embodiment of the present invention.
FIG. 4 is a block diagram showing a conventional nonlinear distortion compensation apparatus.
[Explanation of symbols]
101, 201, 301, 407 Baseband unit 102, 202, 302 I signal 103, 203, 303 Q signal 104, 204, 304, 402 Power calculation unit 105, 205, 305, 406 Distortion compensation calculation unit 106, 306 Distortion compensation Data table 107, 108, 209, 210, 307, 308 D / A conversion unit 109, 309 Table switching control unit 110, 212, 310 Power supply voltage 111, 211, 311 Temperature 112, 213, 312, 411 Radio unit 113, 214 313, 408 Quadrature modulation section 114, 215, 314, 409 Power amplification section 115, 216, 315 Antenna 206 Coefficient update section 207 Distortion compensation basic data 208 Fluctuation approximation formula 403 Reference table 1
404 Reference table 2
405 compensation coefficient calculation unit 410 modulation signal

Claims (7)

A distortion compensation basic data is one distortion compensation data of the plurality of distortion compensation data of the power amplifier corresponding to the variations of the adaptive information that indicates the variation of the previously acquired operation environment, the distortion compensation basic data for the adaptation information A coefficient updating unit that generates a distortion compensation data according to the adaptive information by multiplying a fluctuation approximation formula that approximates the fluctuation of
A distortion compensation calculation unit that compensates for nonlinear distortion of the output IQ signal using the distortion compensation data generated by the coefficient update unit ;
A quadrature modulation unit that quadrature modulates the output IQ signal subjected to nonlinear distortion compensation by the distortion compensation calculation unit ;
A non-linear distortion compensation apparatus comprising: a power amplifying unit that amplifies a modulation signal that is orthogonally modulated by the orthogonal modulation unit.   The nonlinear distortion compensation apparatus according to claim 1, wherein the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to a power supply voltage of the power amplifier.   The nonlinear distortion compensation apparatus according to claim 1, wherein the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to an ambient temperature of the power amplifier.   The nonlinear distortion compensation apparatus according to claim 1, wherein the fluctuation approximation formula approximates a fluctuation of the distortion compensation basic data with respect to a power supply voltage and an ambient temperature of the power amplifier.   The power amplifying unit is a variable power amplifying unit capable of adjusting output power,
  The nonlinear distortion compensation apparatus according to claim 1, further comprising transmission power control means for controlling output power of the variable power amplifier corresponding to the adaptive information.   Furthermore, an IQ amplitude adjustment unit for adjusting the amplitude of the output IQ signal subjected to nonlinear distortion compensation by the distortion compensation calculation unit,
  The nonlinear distortion compensation apparatus according to claim 5, wherein the output power control unit controls the IQ amplitude adjustment unit corresponding to the adaptation information.   Distortion compensation basic data which is one distortion compensation data among a plurality of distortion compensation data of the power amplifying unit corresponding to a change in adaptive information indicating a change in operating environment acquired in advance, and the distortion compensation basic data for the adaptation information A coefficient update step of generating distortion compensation data according to the adaptive information by multiplying by a fluctuation approximation formula approximating the fluctuation of
  A distortion compensation calculation step for nonlinear distortion compensation of the output IQ signal using the distortion compensation data generated in the coefficient update step;
  An orthogonal modulation step of orthogonally modulating the output IQ signal subjected to nonlinear distortion compensation in the distortion compensation calculation step;
  A non-linear distortion compensation method comprising: a power amplification step of amplifying the modulation signal orthogonally modulated in the orthogonal modulation step by the power amplification unit.

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