WO2014141335A1 - Appareil de communication, et procédé de suppression de crête correspondant - Google Patents

Appareil de communication, et procédé de suppression de crête correspondant Download PDF

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Publication number
WO2014141335A1
WO2014141335A1 PCT/JP2013/006536 JP2013006536W WO2014141335A1 WO 2014141335 A1 WO2014141335 A1 WO 2014141335A1 JP 2013006536 W JP2013006536 W JP 2013006536W WO 2014141335 A1 WO2014141335 A1 WO 2014141335A1
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Prior art keywords
signal
baseband signal
suppression
baseband
peak suppression
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PCT/JP2013/006536
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English (en)
Japanese (ja)
Inventor
憲明 田和
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日本電気株式会社
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Priority to JP2015505083A priority Critical patent/JP6070820B2/ja
Publication of WO2014141335A1 publication Critical patent/WO2014141335A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B1/0475—Circuits with means for limiting noise, interference or distortion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2614—Peak power aspects
    • H04L27/2618—Reduction thereof using auxiliary subcarriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2614—Peak power aspects
    • H04L27/2623—Reduction thereof by clipping
    • H04L27/2624—Reduction thereof by clipping by soft clipping

Definitions

  • the present invention relates to a communication apparatus and a peak suppression method thereof, for example, a communication apparatus that transmits a signal obtained by combining a plurality of baseband signals belonging to different frequency bands, and a peak suppression method thereof.
  • OFDM Orthogonal-Frequency-Division-Multiplexing
  • OFDM Orthogonal-Frequency-Division-Multiplexing
  • An OFDM signal is a superposition of subcarrier signals having independent phases, and may have a very high peak power depending on the combination of phases. When such a signal is input to the amplifier, sufficient linearity is required in the input / output characteristics.
  • Patent Documents 1 to 3 propose various methods.
  • Patent Document 1 discloses a technique for performing subtraction with a peak amplitude using a compensation signal having an impulsive property generated based on the peak amplitude. Thereby, in patent document 1, a peak component is reduced, suppressing signal quality degradation which arises at the time of peak component reduction small.
  • a transmitter that suppresses peak power of a transmission signal includes a plurality of peak suppression signal generation means, peak suppression signal synthesis means, and subtraction means.
  • a plurality of peak suppression signal generation means generate a peak suppression signal for suppressing the peak voltage of the transmission signal
  • a peak suppression signal synthesis means generates a peak generated by the plurality of peak suppression signal generation means.
  • a technique is disclosed in which a suppression signal is combined, and a subtracting unit subtracts a combined signal obtained by a peak suppression signal combining unit from a transmission signal. Thereby, in patent document 2, the peak electric power which generate
  • Patent Document 3 a plurality of OFDM signals are generated, a baseband peak suppression unit suppresses each OFDM signal based on these signals, and an IF conversion unit converts each OFDM signal subjected to peak suppression to an intermediate frequency.
  • the intermediate frequency peak suppression means suppresses each of the intermediate frequency signals based on these signals, the combining means combines the peak-suppressed signals having a plurality of intermediate frequencies, and the amplification means Amplifies the combined signal.
  • the baseband peak suppressing means suppresses the peak value by combining the absolute value of each OFDM signal as a predicted peak value, and the intermediate frequency peak suppressing means combines a plurality of intermediate frequency signals. Peak suppression is performed using the absolute value of the result as a predicted peak value.
  • the frequency band of a signal included in a transmission signal (for example, an RF signal) is limited to one, and an RF signal modulated with a carrier wave in a different frequency band is synthesized and output.
  • the common amplifier receives an RF signal obtained by combining the OFDM signals modulated with carriers of different frequency bands. .
  • the peak suppression process is also performed on the intermediate frequency signal, thereby preventing the peak of the combined signal from being reproduced.
  • JP 2004-179813 A JP 2008-47959 A JP 2008-294519 A
  • the present invention has been made to solve the above-described problem, and a communication apparatus and a peak capable of performing peak suppression even on an RF signal obtained by combining a plurality of OFDM signals modulated by carriers of different frequency bands.
  • the purpose is to provide a suppression method.
  • One aspect of a communication apparatus performs peak suppression processing on a first baseband signal and a second baseband signal, and outputs a third baseband signal and a fourth baseband signal.
  • a peak suppressor a first digital-to-analog converter that converts the third baseband signal into an analog signal, a second digital-to-analog converter that converts the fourth baseband signal into an analog signal, and A first frequency converter for converting a frequency of the third baseband signal output from the first digital-analog converter into a frequency of a first carrier wave and outputting a first transmission signal;
  • the frequency of the fourth baseband signal output from the digital-to-analog converter is converted to the frequency of the second carrier belonging to a frequency band different from the first carrier, and
  • a second frequency converter that outputs a transmission signal of the first, a combiner that combines the first transmission signal and the second transmission signal and outputs a third transmission signal, and the third transmission signal
  • an output amplifier for outputting an output signal, wherein the peak suppressor is
  • Generating a second suppression signal generating the third baseband signal by reflecting the first suppression signal in the first baseband signal, and generating the second baseband signal in the second baseband signal.
  • the fourth baseband signal reflecting the suppression signal It is formed.
  • the peak suppression method performs peak suppression processing on the first baseband signal and the second baseband signal, and outputs a third baseband signal and a fourth baseband signal.
  • a first digital-to-analog converter that converts the third baseband signal into an analog signal
  • a second digital-to-analog converter that converts the fourth baseband signal into an analog signal
  • the first A first frequency converter for converting the frequency of the first baseband signal output from the digital-analog converter to a frequency of a first carrier wave and outputting a first transmission signal
  • the second digital signal The frequency of the second baseband signal output from the analog converter is converted to the frequency of the second carrier belonging to a frequency band different from the first carrier, and the second A second frequency converter for outputting a transmission signal, a combiner for combining the first transmission signal and the second transmission signal and outputting a third transmission signal, and the third transmission signal.
  • the third base bar Generates a de signal, it said reflecting the second suppression signal to generate the fourth baseband signal to the second baseband signal.
  • peak suppression can be performed on an output signal obtained by combining a plurality of OFDM signals modulated by carrier waves having different frequencies.
  • FIG. 1 is a block diagram of a communication device according to a first exemplary embodiment.
  • FIG. 3 is a block diagram of a peak suppressor according to the first embodiment.
  • FIG. 3 is a schematic diagram illustrating a frequency band of a baseband signal handled in the communication apparatus according to the first embodiment.
  • 6 is a graph showing a complementary cumulative distribution function of an output signal of the communication device according to the first exemplary embodiment; It is a graph which shows the complementary cumulative distribution function of an output signal at the time of performing the conventional peak suppression process.
  • FIG. 3 is a block diagram of a communication device according to a second exemplary embodiment.
  • FIG. 6 is a block diagram of a communication apparatus according to a third embodiment.
  • FIG. 6 is a block diagram of a communication apparatus according to a fourth embodiment.
  • FIG. 10 is a block diagram of a peak suppressor according to a fourth embodiment.
  • Embodiment 1 Embodiments of the present invention will be described below with reference to the drawings.
  • the communication apparatus according to the first embodiment is capable of outputting a synthesized signal obtained by synthesizing a baseband signal that is modulated by a carrier wave having a frequency that is far away from the frequency allocation. Therefore, when a transmission signal (for example, an OFDM signal) obtained by modulating a baseband signal with a carrier wave having such a large frequency is combined to output a combined signal (for example, an RF signal), the conventional peak suppression method The reason why the peak suppression could not be sufficiently performed will be described in detail.
  • a transmission signal for example, an OFDM signal
  • the peak power is determined for the digital signal, and clipping processing is performed.
  • a synthesized signal obtained by synthesizing a plurality of OFDM signals can use a conventional peak suppression method if the frequencies of the OFDM signals are adjacent to each other at a frequency close to that which can be expressed as a single digital signal.
  • a conventional peak suppression method is used for a synthesized signal obtained by synthesizing OFDM signals in a frequency band far apart
  • clipping processing using a conventional peak suppression method is individually performed on the baseband signal of the OFDM signal before synthesis.
  • An RF signal including OFDM signals in a plurality of frequency bands can be obtained by combining these after up-converting them to the carrier frequency.
  • the peak power to average power ratio (Peak Average Power Ratio, PAPR) of the RF signal obtained in this way is the peak power to average power ratio of a single OFDM signal that has been subjected to peak suppression processing before synthesis.
  • PAPR Peak Average Power Ratio
  • one of the features of the communication apparatus is to provide means and a method for suppressing the peak power of a combined signal obtained by combining signals modulated by carriers in different frequency bands.
  • FIG. 1 is a block diagram of the communication apparatus 1 according to the first embodiment.
  • the communication apparatus 1 according to the first embodiment includes a first OFDM baseband signal generation unit 10, a second OFDM baseband signal generation unit 20, digital analog converters 11 and 21, an up-converter. 12, 22, a peak suppression unit 30, a distortion correction unit 31, a synthesizer 35, an amplifier 36, and a directional coupler 37.
  • the first OFDM baseband signal generation unit 10 outputs the first baseband signal TxBB11.
  • the second OFDM baseband signal generation unit 20 outputs a second baseband signal TxBB21.
  • the first OFDM baseband signal generation unit 10 and the second OFDM baseband signal generation unit 20 are arithmetic devices such as a processor that generates data to be transmitted to the communication partner of the communication device 1, for example.
  • the peak suppression unit 30 performs peak suppression processing on the first baseband signal TxBB11 and the second baseband signal TxBB21, and outputs a third baseband signal TxBB12 and a fourth baseband signal TxBB22. More specifically, the peak suppressor 30 matches the phase of the first carrier and the phase of the second carrier in the combined signal of the first baseband signal TxBB11 and the second baseband signal TxBB12.
  • the power of the combined signal at the time is calculated as the maximum power value, and when the maximum power value is larger than the power threshold, a first suppression signal and a second suppression signal having values other than zero are generated, and the first base A third baseband signal TxBB12 is generated by reflecting the value of the first suppression signal in the band signal TxBB11, and a fourth baseband signal in which the value of the second suppression signal is reflected in the second baseband signal TxBB21 TxBB22 is generated.
  • the distortion correction unit 31 is provided after the peak suppression unit 30 and compares the third baseband signal TxBB12 and the fourth baseband signal TxBB22 with an output signal (for example, an RF signal Txout) to generate an RF signal.
  • a distortion amount of Txout is calculated, and distortion compensation processing is performed on the third baseband signal and the fourth baseband signal so as to reduce the distortion amount.
  • the distortion correction unit 31 includes a predistortion unit 32, a first delay unit (for example, a delay unit 33), and a second delay unit (for example, a delay unit 34).
  • the predistortion unit 32 calculates the distortion amount of the RF signal Txout, and multiplies the third baseband signal TxBB12 and the fourth baseband signal TxBB22 by a distortion compensation coefficient generated according to the magnitude of the distortion amount.
  • the third baseband signal TxBB13 and the fourth baseband signal TxBB23 are output.
  • the predistortion unit 32 also includes a first delay setting value DL1 and a second delay setting value having values corresponding to the difference in delay amount from the input of the predistortion unit 32 to the amplifier 36 of two OFDM signals.
  • the predistortion unit 32 receives a signal between two baseband signals from when the first baseband signal and the second baseband signal are input to the predistortion unit 32 until the third transmission signal reaches the amplifier 36.
  • 1st delay setting value DL1 and 2nd delay setting value DL2 which have a value according to the difference of the amount of delay which arises in 2 are output.
  • the baseband signals before the processing with the distortion compensation coefficient are labeled with TxBB12 and TxBB22, and the baseband signals after the processing with the distortion compensation coefficient are performed with TxBB13 and TxBB23. A reference is attached.
  • the codes of TxBB12 and TxBB22 are used for the baseband signal before the processing using the distortion compensation coefficient, and the codes of TxBB13 and TxBB23 are used for the baseband signal after the processing using the distortion compensation coefficient. Is used.
  • the delay unit 33 delays the third baseband signal TxBB13 according to the first delay setting value DL1.
  • the delay unit 34 delays the fourth baseband signal in accordance with the second delay setting value.
  • the digital-analog converter 11 converts the third baseband signal TxBB13 into an analog signal.
  • the digital-analog converter 21 converts the fourth baseband signal TxBB23 into an analog signal.
  • the up converter 12 is a first frequency converter.
  • the up-converter 12 converts the frequency of the third baseband signal TxBB13 output from the first digital-analog converter 11 into the frequency of a first carrier wave (for example, a first local signal) and performs first transmission. Output a signal.
  • the up converter 22 is a second frequency converter.
  • the up-converter 22 sets the frequency of the fourth baseband signal TxBB 23 output from the second digital-analog converter 21 to a second carrier (for example, a second local signal) belonging to a frequency band different from the first carrier. ) To output a second transmission signal.
  • the synthesizer 35 synthesizes the first transmission signal and the second transmission signal and outputs a third transmission signal.
  • the amplifier 36 amplifies the third transmission signal and outputs a signal (for example, an RF signal Txout).
  • the directional coupler 37 outputs a small part of the RF signal Txout transmitted to the antenna to the distortion correction unit 31 as a feedback signal.
  • the peak suppression unit 30 and the distortion correction unit 31 which are one of the features of the communication device 1 according to the first embodiment will be described in detail.
  • the peak suppression unit 30 will be described in detail.
  • a detailed block diagram of the peak suppressor 30 is shown in FIG.
  • the peak suppression unit 30 includes a tone signal generation unit 41, filters 42 and 43, and subtractors 44 and 45.
  • the tone signal generation unit 41 combines the first transmission signal generated from the first baseband signal TxBB11 and the second transmission signal generated from the second baseband signal TxBB21. Based on the maximum power of the signal, a first suppression signal (for example, the first impulse signal I1) and a second suppression signal (for example, the second impulse signal I2) are output. More specifically, the tone signal generation unit 41 includes a phase coincidence power calculation unit 51, a threshold power calculation unit 52, a power determination unit 53, an impulse signal generator 54, and a zero signal generator 55.
  • phase coincidence power calculation unit 51 matches the phase of the first local signal and the phase of the second local signal in the combined signal of the first baseband signal TxBB11 and the second baseband signal TxBB21. Is calculated as the maximum power value Pmax.
  • the maximum power value Pmax can be expressed by equation (1). Note that t in the expression (1) indicates the time when the signal is sampled.
  • the threshold power calculation unit 52 calculates an average power value in a predetermined period of a combined signal obtained by combining the first baseband signal TxBB11 and the second baseband signal TxBB21, and a clipping coefficient C set in advance for the average power value.
  • the power threshold value Pth can be calculated from the following equations (2) to (4).
  • TxBB (t) in equation (2) is the sum of the powers of the two baseband signals at time t.
  • Pmean in the equation (3) is an average power during a predetermined period n.
  • a value of about 7 dB is set as the clipping coefficient C in the equation (4). The smaller the clipping coefficient C is, the lower the peak power-to-average power ratio PAPR is.
  • the amplifier 36 is preferable from the viewpoint of distortion characteristics and power efficiency.
  • the modulation accuracy EVM Error Vector Magnitude
  • the clipping coefficient C is set to an appropriate value in consideration of the trade-off relationship between the peak power to average power ratio and the modulation accuracy EVM. It is preferred that Further, the clipping coefficient C may be varied according to the average power Pmean or the power levels of the first baseband signal TxBB11 and the second baseband signal TxBB21.
  • the power determining unit 53 compares the maximum power value Pmax and the power threshold value Pth, and switches between the first enable signal EN1 and the second enable signal EN2 to be enabled. Specifically, if the maximum power value Pmax is larger than the power threshold value Pth, the power determination unit 53 enables the first enable signal EN1 and disables the second enable signal EN2. Thereby, when the maximum power value Pmax is larger than the power threshold value Pth, the impulse signal generator 54 is in an operating state and the zero signal generator 55 is in a stopped state. On the other hand, when the maximum power value Pmax is equal to or smaller than the power threshold value Pth, the power determination unit 53 disables the first enable signal EN1 and enables the second enable signal EN2. Thereby, when the maximum power value Pmax is equal to or less than the power threshold value Pth, the impulse signal generator 54 is stopped and the zero signal generator 55 is activated.
  • the impulse signal generator 54 generates impulse signals (for example, the first impulse signal I1 and the second impulse signal I2) having magnitudes calculated based on the maximum power value Pmax, the power threshold value Pth, and the weighting factors a1 and a2. Generate.
  • the first impulse signal I1 is applied to the first baseband signal TxBB11
  • the second impulse signal I2 is applied to the second baseband signal TxBB21.
  • the first impulse signal I1 and the second impulse signal I2 can be calculated by the equations (5) and (6).
  • the weighting factors a1 and a2 are stored in advance in a storage unit (not shown) such as a nonvolatile memory.
  • the zero signal generator 55 generates a zero signal whose value is zero.
  • the zero signal is an impulse signal having a value of zero
  • the zero signal generator 55 according to the first embodiment generates a first impulse signal I1 and a second impulse signal I2 having a value of zero. That is, the first impulse signal I1 and the second impulse signal I2 output from the zero signal generator 55 are expressed by the equations (7) and (8).
  • the filter 42 outputs the first impulse signal I1 in which the level of the out-of-band signal is attenuated to the subtractor 44 as a first suppression signal.
  • the filter 43 outputs the second impulse signal I2 in which the level of the out-of-band signal is attenuated to the subtracter 45 as a second suppression signal.
  • the impulse signals input to the filters 42 and 43 and the output impulse signals are the same with respect to necessary signal components, and thus the same reference numerals are given to these signals.
  • the subtractor 44 is a first subtracter, and generates a third baseband signal TxBB12 by subtracting a first suppression signal (for example, the first impulse signal I1) from the first baseband signal TxBB11. To do. That is, the third baseband signal TxBB12 is expressed by the equation (9).
  • the subtracter 45 is a second subtracter, and generates a fourth baseband signal TxBB22 by subtracting a second suppression signal (for example, the second impulse signal I2) from the second baseband signal TxBB21. To do. That is, the fourth baseband signal TxBB22 is expressed by equation (10).
  • the third baseband signal TxBB12 and the fourth baseband signal TxBB22 are converted into the first baseband signal TxBB11 and The term of the second baseband signal TxBB21 is eliminated. That is, the third baseband signal TxBB12 and the fourth baseband signal TxBB22 are signals that are clipped with the power threshold value Pth on the basis of the power maximum value Pmax.
  • the peak suppression unit 30 sets the maximum power when the first baseband signal TxBB11 and the second baseband signal TxBB21 are combined after being up-converted with the respective local signals to the power threshold Pth or less. Next, peak suppression processing is performed on the baseband signal.
  • the effect of the peak suppression processing by the peak suppression unit 30 will be described. Therefore, first, an example of the frequency band of the first transmission signal generated from the first baseband signal TxBB11 and the second transmission signal generated from the second baseband signal TxBB21 in the communication device 1 is provided. A diagram for explanation is shown in FIG. As shown in FIG. 3, in the communication apparatus 1, an OFDM signal whose center frequency fc1 belongs to the 800 MHz band is generated as the first transmission signal, and an OFDM signal whose center frequency fc2 belongs to the 2.6 GHz band as the second transmission signal. And the first and second transmission signals are combined to generate a third transmission signal.
  • FIG. 4 is a graph showing the complementary cumulative distribution function CCDF when the first transmission signal and the second transmission signal in the frequency band shown in FIG. 3 are combined in the communication apparatus 1 according to the first embodiment.
  • the RF signal output from the amplifier 36 is indicated by Txout.
  • the first transmission signal is OFDM1 and the second transmission signal is OFDM2.
  • CCDF of AWGN Additional White Gaussian Noise
  • the CCDF of the RF signal Txout obtained by synthesizing the first transmission signal OFDM1 and the second transmission signal OFDM2 is greatly reduced compared to AWGN.
  • the conventional peak suppression method is a method of performing synthesis processing and up-conversion processing after performing peak suppression processing only on each local signal.
  • CCDF is suppressed for individual OFDM signals.
  • the CCDF of the RF signal Txout generated after combining these signals is less suppressed than the individual OFDM signal. That is, by using the communication device 1 according to the first embodiment, it is possible to efficiently suppress the peak power as compared with the communication device to which the conventional peak suppression method is applied.
  • the distortion correction unit 31 will be described in detail. First, the influence of the delay time difference on the distortion characteristics due to the difference in the transmission path will be described.
  • the RF signal Txout fed back to the predistortion unit 32 is a carrier wave applied in the upconverters 12 and 22. If the influence is ignored, it can be expressed by equation (11).
  • the RF signal Txout is expressed by Expression (12).
  • peak suppression is appropriately performed by combining the third baseband signal TxBB12 and the fourth baseband signal TxBB22 in a state expressed by the equation (11).
  • the RF signal Txout is in a state expressed by the equation (12)
  • peak suppression is not performed correctly, and there is a problem that the peak power to average power ratio PAPR increases.
  • the above problem is solved by using the distortion correction unit 31.
  • the distortion correction unit 31 first compares the RF signal Txout with the third baseband signal TxBB12 and the fourth baseband signal TxBB22 output from the peak suppression unit 30 in the predistortion unit 32, and the RF signal Txout. The amount of distortion is calculated. Then, the predistortion unit 32 performs distortion compensation calculation by multiplying the third baseband signal TxBB12 and the fourth baseband signal TxBB22 by a distortion compensation coefficient generated according to the magnitude of the calculated distortion amount.
  • TxBB13 and TxBB23 are attached as codes of the third baseband signal TxBB12 and the fourth baseband signal TxBB22 after the distortion compensation calculation.
  • the predistortion unit 32 obtains a delay amount in the process of comparing the third baseband signal TxBB12 and the fourth baseband signal TxBB22 with the RF signal Txout, and has a value corresponding to the difference. 1 delay setting value DL1 and 2nd delay setting value DL2 are calculated.
  • the subtractor 44 delays the third baseband signal TxBB12 according to the first delay setting value DL1, and the subtractor 45 delays the fourth baseband signal TxBB12 according to the second delay setting value DL2.
  • the baseband signal TxBB22 is delayed.
  • a zero delay amount is set as the first delay setting value DL1
  • the second delay setting value is set.
  • a delay amount ⁇ t is set as DL2.
  • the delay time between the two transmission paths for transmitting the baseband is known in advance, the delay time can be set in advance in the delay units 33 and 34 without using the predistortion unit 32. This eliminates the need to use the predistortion unit 32.
  • the communication apparatus 1 generates two transmission signals by converting the frequency of the two baseband signals into the frequency band of the RF signal by the up-converters 12 and 13, and generates two transmission signals. Is synthesized by the synthesizer 35 to generate an RF signal Txout, whereby an RF signal Txout including a transmission signal in a frequency band far away can be generated.
  • the communication device 1 uses the peak suppression unit 30 to base the maximum power value Pmax of the transmission signal at the time when the phases of two carrier waves (local signals) used for baseband signal modulation match.
  • the peak suppression process is performed on the baseband signal so that the maximum power value Pmax is calculated from the band signal and does not exceed the power threshold value Pth.
  • the communication apparatus 1 according to the first embodiment can reduce the peak power of the RF signal Txout and suppress the peak power to average power ratio PAPR.
  • the communication device 1 calculates the threshold power Pth from the average power value of the RF signal Txout generated from the baseband signal. Thereby, the communication apparatus 1 according to the first embodiment can adaptively change the power threshold Pth with respect to the change in the baseband signal sequence.
  • the communication device 1 uses the distortion correction unit 31 to achieve a high peak suppression effect even when there is a difference in delay time between a plurality of transmission paths that transmit baseband signals. Can be maintained.
  • Embodiment 2 In the second embodiment, a communication device 2 that is another form of the communication device 1 according to the first embodiment will be described.
  • FIG. 6 shows a block diagram of the communication device 2 according to the second embodiment.
  • the same components as those described in the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and description thereof is omitted.
  • the communication device 2 according to the first embodiment is obtained by deleting the distortion correction unit 31 from the communication device 1 according to the first embodiment. That is, the communication device 2 according to the second embodiment is the same as the communication device 1 according to the first embodiment, in which the delay times of the delay unit 33 and the delay unit 34 of the distortion correction unit 31 are both zero.
  • the distortion correction unit 31 is not mounted.
  • the communication device 2 according to the second embodiment may be used. Thereby, since the distortion correction unit 31 can be deleted, the communication device 2 can reduce the circuit area as compared with the communication device 1.
  • FIG. 7 shows a block diagram of the communication device 3 according to the third embodiment.
  • the same components as those described in the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and description thereof is omitted.
  • the communication device 3 according to the third embodiment is obtained by deleting the distortion correction unit 31 from the communication device 1 according to the first embodiment and replacing the peak suppression unit 30 with a peak suppression unit 60. is there.
  • the peak suppression unit 60 includes a first peak suppression unit 61 and a second peak suppression unit 62.
  • the first peak suppressing unit 61 and the second peak suppressing unit 62 are connected in multiple stages.
  • the first peak suppressor 61 and the second peak suppressor 62 have the same configuration as that of the peak suppressor 30, respectively.
  • the first peak suppressor 61 and the second peak suppressor 62 are based on different values of the clipping coefficient and the weighting coefficient.
  • a second suppression signal is generated. Note that the clipping coefficient and the weighting coefficient may have the same value in the first peak suppressing unit 61 and the second peak suppressing unit 62.
  • the peak power can be suppressed while suppressing the excessive subtraction in the clipping process by making the peak suppression unit in a multi-stage connection, it is possible to suppress the deterioration of the modulation accuracy EVM.
  • FIG. 8 shows a block diagram of the communication device 4 according to the fourth embodiment.
  • the same components as those described in the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and description thereof is omitted.
  • the communication device 4 according to the fourth embodiment is obtained by deleting the distortion correction unit 31 from the communication device 1 according to the first embodiment and replacing the peak suppression unit 30 with a peak suppression unit 70. is there.
  • the peak suppression unit 70 includes a clipping processing unit 71 and filters 42 and 43.
  • the clipping processing unit 71 generates the third baseband signal TxBB12 and the fourth baseband signal TxBB22 having the same peak suppression effect without performing the subtraction processing used in the peak suppression unit 30 of the first embodiment.
  • a detailed block diagram of the clipping processing unit 71 is shown in FIG. In FIG. 9, filters 42 and 43 associated with the clipping processing unit 71 are also illustrated.
  • the clipping processing unit 71 includes a phase coincidence power calculation unit 51, a threshold power calculation unit 52, a power determination unit 53, a signal level suppression unit 72, and a signal passage unit 73.
  • phase coincidence power calculation unit 51, the threshold power calculation unit 52, and the power determination unit 53 have been described in the first embodiment, description thereof is omitted here.
  • the signal level suppression unit 72 operates based on the first enable signal EN1 that is enabled when the maximum power value Pmax is larger than the power threshold value Pth.
  • the signal level suppression unit 72 generates first and second suppression signals in the block, and uses the first and second suppression signals, the maximum power value Pmax, and the power threshold value Pth to generate the third suppression signal.
  • a baseband signal TxBB12 and a fourth baseband signal TxBB22 are generated.
  • the signal level suppression unit 72 generates a value expressed by the equation (13) as the first suppression signal I1, and generates a value expressed by the equation (14) as the second suppression signal I2. . Then, the signal level suppression unit 72 generates the third baseband signal TxBB12 and the fourth baseband signal TxBB22 using the first suppression signal I1 and the second suppression signal I2.
  • the third baseband signal TxBB12 is expressed by equation (15)
  • the fourth baseband signal TxBB22 is expressed by equation (16).
  • the signal passing unit 73 operates based on the second enable signal EN2 that is enabled when the maximum power value Pmax is less than or equal to the power threshold value Pth.
  • the signal passing unit 73 outputs the input first baseband signal TxBB11 and second baseband signal TxBB21 as they are as the third baseband signal TxBB12 and the fourth baseband signal TxBB22. That is, the third baseband signal TxBB12 and the fourth baseband signal TxBB22 output from the signal passing unit 73 are expressed by Expressions (17) and (18).
  • the peak suppression unit 70 can output a signal equivalent to the signal output by the peak suppression unit 30. That is, also in the communication device 4 according to the fourth embodiment, a high peak suppression effect can be obtained with respect to the RF signal Txout including the transmission signal in a frequency band separated from the communication device 1 according to the first embodiment.
  • the circuit scale and the processing time can be reduced compared to the communication device 1 according to the first embodiment. be able to.
  • the present invention is not limited to OFDM modulation, but may be used in other modulation schemes such as W-CDMA and SD-FDMA. Can do. That is, by using the present invention, it is possible to generate a high-quality RF signal not only in multi-channel communication but also in multi-standard communication.
  • 1 to 4 communication device 20 OFDM baseband signal generation unit 11, 21 digital-analog converter 12, 22 up-converter 30, 60, 61, 62, 70 peak suppression unit 31 distortion correction unit 32 predistortion unit 33, 34 delay Unit 35 synthesizer 36 amplifier 37 directional coupler 41 tone signal generation unit 42, 43 filter 44, 45 subtractor 51 phase coincidence power calculation unit 52 threshold power calculation unit 53 power determination unit 54 impulse signal generator 55 zero signal generation 71 Clipping processing unit 72 Signal level suppressing unit 73 Signal passing unit TxBB11, TxBB12, TxBB13 Baseband signals TxBB21, TxBB22, TxBB23 Baseband signals DL1, DL2 Delay setting value Pmax Maximum power value Pth Power threshold EN1, N1 enable signal I1, I2 impulse signal

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Transmitters (AREA)

Abstract

La présente invention se rapporte à un appareil de communication qui comprend : des moyens de suppression de crête (30) ; des moyens de conversion numérique/analogique (11, 21) ; des moyens de conversion de fréquence (12, 22) ; des moyens de combinaison (35) ; et des moyens d'amplification (36). Les moyens de suppression de crête selon l'invention (30) calculent, en tant qu'une valeur de puissance maximale, la puissance du signal qui, parmi des signaux combinés obtenus en combinant des premiers signaux dans la bande de base (TxBB11) à des deuxièmes signaux dans la bande de base (TxBB21), apparaît quand la phase d'une première porteuse coïncide avec celle d'une porteuse secondaire. Les moyens de suppression de crête (30) génèrent des premier et second signaux de suppression qui ont des valeurs différentes de zéro quand la valeur de puissance maximale est supérieure à une valeur de seuil de puissance. Les moyens de suppression de crête (30) commandent ensuite au premier signal dans la bande de base de réfléchir la valeur du premier signal de suppression, de sorte à générer ainsi un troisième signal dans la bande de base (TxBB12) ; et ils commandent également au deuxième signal dans la bande de base de réfléchir la valeur du second signal de suppression, de sorte à générer ainsi un quatrième signal dans la bande de base (TxBB22).
PCT/JP2013/006536 2013-03-15 2013-11-06 Appareil de communication, et procédé de suppression de crête correspondant WO2014141335A1 (fr)

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JP2002044054A (ja) * 2000-07-25 2002-02-08 Hitachi Kokusai Electric Inc リミッタ回路付きキャリア合成送信回路
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