WO2014136437A1 - 無線送信装置および無線送信方法 - Google Patents
無線送信装置および無線送信方法 Download PDFInfo
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- WO2014136437A1 WO2014136437A1 PCT/JP2014/001177 JP2014001177W WO2014136437A1 WO 2014136437 A1 WO2014136437 A1 WO 2014136437A1 JP 2014001177 W JP2014001177 W JP 2014001177W WO 2014136437 A1 WO2014136437 A1 WO 2014136437A1
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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
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/08—Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/0001—Arrangements for dividing the transmission path
- H04L5/0003—Two-dimensional division
- H04L5/0005—Time-frequency
- H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
- H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT the frequencies being arranged in component carriers
Definitions
- the present invention relates to a wireless transmission device and a wireless transmission method, and more particularly to a wireless transmission device and a wireless transmission method using a plurality of frequency bands.
- nonlinearity of a power amplifier that amplifies a radio frequency (Radio Frequency: RF) signal is a major factor that distorts the RF signal to be transmitted.
- the distortion of the RF signal generates leakage power that leaks outside the desired frequency band used for transmission.
- linear modulation is mainly used to improve spectral efficiency. In this linear modulation, a strict limit is set for the leakage power outside the desired band generated by the distortion of the RF signal. Therefore, suppressing distortion of the RF signal to be transmitted is an important technical problem in the wireless transmission device.
- CA Carrier Aggregation: CA
- CA Carrier Aggregation: CA
- a wide band can be secured by bundling a plurality of bands, and the transmission speed can be increased.
- the CA technology it is possible to perform communication corresponding to a case where the bandwidth allocation of a plurality of operators is intermittent or a bandwidth is shared.
- CA technology is classified according to the frequency arrangement of each carrier.
- One of them is an inter-band non-continuous CA mode in which carrier frequencies are arranged such that the difference ⁇ f between carrier frequencies is sufficiently larger than the modulation bandwidth f BB of the RF signal of each carrier.
- communication stability can be improved by performing simultaneous communication using a plurality of carrier frequencies having different propagation characteristics.
- a wireless transmission device and a wireless transmission method for transmitting RF signals in a plurality of bands are required. Even in such a wireless transmission device, it is required to suppress distortion of the RF signal. Further, from the viewpoint of downsizing and cost reduction of the apparatus, it is desirable that a wireless transmission apparatus compatible with CA technology can amplify and transmit RF signals of a plurality of bands with a single power amplifier.
- FIG. 16 shows a configuration of a related wireless transmission device described in Patent Document 2.
- the related wireless transmission device 100 includes two blocks, a dual band transmitter 130 and a predistortion unit 120.
- the dual band transmitter 130 has a function of simultaneously transmitting an RF signal having a carrier frequency f c1 (band 1) and an RF signal having a carrier frequency f c2 (band 2).
- the band 1 baseband signal 115A passes through a low-pass filter 135A and is converted into an RF signal having a carrier frequency f c1 in a frequency converter including a local oscillation (LO) signal generator 140A and a mixer 145A.
- the baseband signal 115B of the band 2 via a low-pass filter 135B, and is converted into an RF signal of the carrier frequency f c2 in LO signal generator 140B and a frequency converter consisting of the mixer 145B.
- the RF signals of carrier frequencies f c1 and f c2 are combined by power combiner 150 and then input to power amplifier 160.
- the power amplifier 160 simultaneously amplifies the RF signals of the carrier frequencies f c1 and f c2 and outputs it as an RF signal 170.
- the predistortion unit 120 has a function of compensating for distortion of the RF output signal 170 composed of the band 1 and the band 2 generated in the dual band transmitter 130. That is, the predistortion unit 120 cancels out the non-linearity of the dual band transmitter 130 by providing a non-linear input / output characteristic opposite to the input / output characteristic of the dual band transmitter 130.
- the band 1 component of the RF output signal 170 depends on both the band 1 baseband signal 115 A and the band 2 baseband signal 115 B input to the dual band transmitter 130.
- the band 2 component of the RF output signal 170 depends on both the band 1 baseband signal 115 A and the band 2 baseband signal 115 B input to the dual band transmitter 130.
- the predistorter 125A generates and outputs a band 1 baseband signal 115A from both the band 1 input baseband signal 110A and the band 2 input baseband signal 110B. To do.
- predistorter 125B generates and outputs band 2 baseband signal 115B from both band 1 input baseband signal 110A and band 2 input baseband signal 110B.
- JP 2012-216969 A (paragraph [0005]) US Patent Application Publication No. 2010/0316157 (paragraph [0042], FIG. 10)
- the related wireless transmission device 100 described above has the following problems.
- the band 1 RF signal input to the power amplifier 160 included in the related wireless transmission device 100 is x 1 (t), and the band 2 RF signal is x 2 (t).
- the complex amplitudes of the RF signals x 1 (t) and x 2 (t) are b x1 (t) and b x2 (t), respectively.
- the power amplifier 160 amplifies signals of two bands at the same time, the nonlinear characteristic of the power amplifier 160 depends on a complex amplitude set [b x1 (t), b x2 (t)] of two input signals.
- the predistortion unit 120 outputs baseband signals [b xPD1 (t), b xPD2 (t)] of band 1 and band 2 to which distortion compensation by predistortion is applied. Then, due to the delay in the path from the output of the predistortion unit 120 to the input of the power amplifier 160, the complex amplitude of the band 1 and band 2 RF signals input to the power amplifier 160 becomes [b xPD1 (t ⁇ ( ⁇ d + ⁇ c )), b xPD2 (t ⁇ c )]. At this time, there arises a problem that the distortion of the RF output signal 170 deteriorates due to the synchronization shift ⁇ d between the band 1 and the band 2.
- the nonlinear characteristic of the power amplifier 160 depends on a set of two input signals [b x1 (t), b x2 (t)]. Therefore, the input signal is [b xPD1 (t), b xPD2 (t)] and the case of [b xPD1 (t ⁇ ( ⁇ d + ⁇ c )), b xPD2 (t ⁇ c )].
- the power amplifier 160 exhibits different characteristics.
- the RF input signals of the two bands are different depending on the delay time difference in the path from the input of the predistortion unit 120, which is the distortion compensation circuit of each band, to the input of the power amplifier 160.
- a synchronization shift ⁇ d occurs.
- the related wireless transmission device 100 has a problem that an increase in the distortion amount of the RF output signal 170 due to the influence of the synchronization shift ⁇ d is inevitable.
- An object of the present invention is to solve the above-described problem that in a wireless transmission device that transmits RF signals of a plurality of bands, the distortion amount of an output signal increases due to a difference in delay time in a plurality of paths.
- a wireless transmission device and a wireless transmission method are provided.
- a wireless transmission device of the present invention includes a multiband RF signal generator that carries a plurality of input baseband signals on carrier waves of different frequencies and outputs them as radio frequency signals, and a power amplifier that amplifies and outputs the radio frequency signals.
- a distortion compensation control signal generator for applying a distortion compensation function for compensating the distortion characteristics of the power amplifier to a plurality of input baseband signals, and a delay time of each of the plurality of input baseband signals received by the multiband RF signal generator.
- a transmitter delay correction unit that corrects the difference.
- the radio transmission method of the present invention corrects the difference in delay time received by each of the plurality of input baseband signals when generating the radio frequency signal in which the plurality of input baseband signals are respectively conveyed to carriers of different frequencies, A plurality of input baseband signals whose delay time differences are corrected are each subjected to a distortion compensation function that compensates for distortion characteristics when the radio frequency signal is amplified.
- the wireless transmission device and the wireless transmission method of the present invention it is possible to suppress an increase in distortion amount in an output signal caused by a difference in delay time in a plurality of paths.
- FIG. 1 It is a block diagram which shows the structure of the radio
- FIG. 2 It is a figure which shows the result of having measured the distortion amount of RF signal output from the power amplifier with which the radio
- FIG. It is a block diagram which shows the structure of a related wireless transmitter. It is a block diagram which shows the structure of the radio
- a wireless transmission device includes a power amplifier corresponding to a carrier aggregation (CA) technology capable of simultaneously amplifying signals of a plurality of frequencies generated by a signal generator.
- CA carrier aggregation
- the wireless transmission device includes a multiband RF signal generator, a power amplifier, a distortion compensation control signal generation unit, and a transmitter delay correction unit.
- the multiband RF signal generator conveys a plurality of input baseband signals to carrier waves of different frequencies, and outputs them as radio frequency (RF) signals.
- the power amplifier simultaneously amplifies and outputs RF signals composed of a plurality of frequency carriers output from the multiband RF signal generator.
- the distortion compensation control signal generation unit outputs a plurality of input baseband signals by applying a distortion compensation function for compensating for the distortion characteristics of the power amplifier. That is, the distortion compensation control signal generation unit applies a distortion compensation function to a plurality of input baseband signals input from the transmitter delay correction unit.
- the distortion compensation function is determined based on a plurality of input baseband signals and an output baseband signal carried by RF signals of a plurality of carrier frequencies output from the power amplifier.
- the distortion compensation control signal generation unit uses this distortion compensation function to generate a corrected baseband signal for removing distortion of the RF signal in each carrier frequency band output from the power amplifier.
- the transmitter delay correction unit corrects the difference in delay received by each of the plurality of input baseband signals in the multiband RF signal generator. That is, the transmitter delay correction unit corrects the synchronization between the plurality of input baseband signals so as to correct the delay time difference between the bands generated by the RF signal generator, and outputs the corrected signal to the distortion compensation control signal generation unit.
- the synchronization shift caused by the delay time in the path from the distortion compensation control signal generation unit to the power amplifier that is, the synchronization between the bands of the input signal of the power amplifier.
- the deviation can be corrected by the transmitter delay correction unit.
- FIG. 1 is a block diagram showing a configuration of a radio transmission apparatus according to the first embodiment of the present invention.
- the wireless transmission apparatus 1000 according to the present embodiment includes at least a transmitter delay correction unit 1101, a distortion compensation control signal generation unit 1102, a multiband RF signal generator 1002, and a power amplifier 1003.
- the transmitter delay correction unit 1101 is a characteristic configuration of the wireless transmission device 1000 according to the present embodiment.
- the wireless transmission device 1000 has a function of transmitting RF signals in a frequency band of a plurality of carriers at the same time.
- the number of bands to be transmitted is “n”.
- the wireless transmission device 1000 performs different operations in a training period for specifying nonlinear characteristics of the power amplifier 1003 and a transmission period for transmitting information signals. That is, the wireless transmission device 1000 identifies the nonlinear characteristic of the power amplifier 1003 during the training period. In the transmission period, distortion compensation of the RF output signal of the power amplifier 1003 is performed based on the specified nonlinear characteristic.
- the transmitter delay correction unit 1101, n-number of base band signal z (t) [z 1 (t), ⁇ , z n (t)] is the terminal 1011 1, ..., via the 1011 n Is input.
- w (t) [w 1 (t), ⁇ , w n (t)] terminal 1012 1 as a, ... it is output to 1012 n.
- the multiband RF signal generator 1002 has delay times ⁇ TX1 ,..., ⁇ TXn in bands 1 ,.
- Signal x (t) [x 1 (t), ..., x n (t)] is measured with an external measuring instrument such as an oscilloscope, and each of input signal w (t) and output signal x (t) It can be determined by comparing the components.
- Each of the band components x 1 (t),..., X n (t) of the RF signal x (t) input simultaneously from the terminal 1013 to the power amplifier 1003 is amplified, and the RF signal y (t) is supplied to the terminal 1014.
- b yn (t) g n [b x1 (t), ..., b xn (t)]
- g 1 ,..., G n are nonlinear functions with n variables b x1 (t),..., B xn (t) as arguments, and input / output in each band of the power amplifier 1003. It represents the nonlinearity of the characteristics.
- Equation (3) The same content as equation (2) can also be expressed by equation (3) below.
- b y (t) g [b x (t)] (3)
- g is a non-linear mapping, and functions g 1 ,..., G n are collectively described.
- equation (4) the relationship between the input and output signals of the power amplifier 1003 can also be described by the following equation (4) in which the relationship between the input and output is reversed from the equation (2).
- b x1 (t) h 1 [b y1 (t), ..., b yn (t)], ..., (4)
- b xn (t) h n [b y1 (t), ..., b yn (t)],
- h 1 ,..., H n are nonlinear functions with n variables b y1 (t),..., B yn (t) as arguments.
- equation (5) the same content as equation (4) can also be expressed by equation (5) below.
- h is a non-linear mapping
- functions h 1 ,..., H n are collectively described.
- the non-linear map g in Expression (3) and the non-linear map h in Expression (5) are in a reverse mapping relationship with each other.
- variable delay means 1101 kj 1,..., N
- Variable delay means 1101 delays the time tau kj in kj can be freely set. For example, the delay time ⁇ kj can be set as shown in the following equation (6).
- ⁇ C is a constant delay time, and can be an arbitrary value.
- it is desirable that ⁇ C Max (
- ) because the delay time ⁇ kj (k, j 1,..., N) to be mounted must be non-negative.
- Max represents the maximum value.
- the baseband signal v jk (t) output to the terminal 1021 kj is input to the distortion compensation control signal generation unit 1102.
- the multiband RF signal generator 1002 has components w 1 (t),...
- the complex amplitude b x (t) [b x1 (t),..., B xn (t)] of the RF signal x (t) input to the power amplifier 1003 via the terminal 1013 is the multiband RF.
- the complex amplitude z in (t) [z 1 (t ⁇ TX1 ),..., Z n (t ⁇ ) of the RF input signal of the power amplifier 1003 during training defined on the right side of the equation (1).
- equation (8) can be summarized as equation (9) below.
- b x (t) h [z in (t ⁇ C )] (9)
- the RF signal x (t) having the complex amplitude b x (t) in Expression (9) is input to the power amplifier 1003, and the RF signal y (t) having the complex amplitude b y (t) is input from the power amplifier 1003 to the terminal 1014. Is output.
- the multiband RF signal y (t) output to this terminal 1014 is used for transmission.
- the wireless transmission device 1000 in the wireless transmission device 1000 according to the present embodiment, the influence of the nonlinearity g of the power amplifier 1003 is removed from the complex amplitude b y (t) of the RF signal output from the power amplifier 1003. I understand that. As a result, the original baseband signal z (t) input to the wireless transmission device 1000 is carried and transmitted to the RF output signal of the power amplifier 1003 without distortion. That is, according to the wireless transmission device of the present embodiment, it is possible to suppress an increase in the distortion amount in the output signal caused by the difference in delay time in a plurality of paths.
- FIGS. 2A and 2B show results of measuring the distortion amount of the RF signal y (t) output from the power amplifier 1003 in the wireless transmission device 1000 shown in FIG.
- a case where a 2-band RF input signal is transmitted is shown.
- FIG. 2A shows the result of measurement for band 1
- FIG. 2B shows the result of measurement for band 2.
- DPD distortion pre-distortion
- an adjacent channel leakage power ratio Adjacent Channel leakage Power Ratio: ACPR
- a modulated wave of a WCDMA (Wideband Code Division Multiple Access (registered trademark)) signal is used for both band 1 and band 2 as the baseband signal z (t) to be transmitted. .
- WCDMA Wideband Code Division Multiple Access
- the horizontal axis represents the synchronization shift time ⁇ d of the two-band RF input signal.
- the complex amplitude when ⁇ d ⁇ 0 is [b xPD1 ( t ⁇ d ), b xPD2 (t)].
- ⁇ d 0, it can be confirmed from the results of FIGS.
- FIG. 3 shows a configuration of a related wireless transmission device 200 in which the transmitter delay correction unit 1101 is not installed. This corresponds to the configuration of the related wireless transmission device 100 shown in FIG.
- the complex amplitude b x (t) [b x1 (t),..., B xn (t)] of the RF signal input to the power amplifier 1003 is the band 1 in the multiband RF signal generator 1002.
- the waveform represented by the following equation (12) is obtained by the delay times ⁇ TX1 ,..., ⁇ TXn of n.
- the RF output signal of the power amplifier 1003 cancels the mapping h having the complex amplitude and the nonlinearity g of the power amplifier. Therefore, the baseband signal z (t) can be transmitted and transmitted to the RF output signal of the power amplifier 1003 without being distorted.
- the transmitter delay correction unit 1101 which is a characteristic configuration of the wireless transmission device 1000 according to the present embodiment branches the input baseband signal carried by one carrier wave into the number of different frequencies (bands). Each input baseband signal is provided with a delay time. Each of these delay times is a delay that an input baseband signal carried by one carrier receives in a multiband RF signal generator, and a delay that an input baseband signal carried by another carrier receives in a multiband RF signal generator. And the difference.
- the transmitter delay correction unit 1101 allows each component [z 1 (t),..., Z n of the original baseband signal z (t) to satisfy the above-described conditions. It is possible to perform an operation of applying synchronous control to (t)].
- This condition is that each band component [b x1 (t),..., B xn (t)] of the complex amplitude b x (t) of the RF signal at the input of the power amplifier 1003 is a distortion compensation function h 1 , ..., the waveform is generated by substituting the same argument for h n ".
- the wireless transmission device 1000 of the present embodiment even when a power amplifier having nonlinear input / output characteristics is used in multiband simultaneous transmission, the baseband signal z (t) is not distorted. Transmission can be performed by carrying the RF output signal y (t) of the power amplifier.
- FIG. 4 is a block diagram illustrating a configuration of the wireless transmission device 2000 according to the present embodiment.
- the wireless transmission device 2000 includes a predistortion unit 1001, a multiband RF signal generator 1002, a power amplifier 1003, and a demodulator 1004.
- the predistortion unit 1001 includes a transmitter delay correction unit 1101, a distortion compensation control signal generation unit 1102, an entire path delay correction unit 1103, and a distortion characteristic calculation unit 1104.
- the wireless transmission device 2000 has a function of transmitting RF signals of a plurality of bands simultaneously, similarly to the wireless transmission device 1000 according to the first embodiment. Based on the nonlinear characteristic of the power amplifier 1003 specified during the training period, distortion compensation of the RF output signal of the power amplifier 1003 is performed during the transmission period.
- the wireless transmission device 2000 identifies the nonlinear characteristic of the power amplifier 1003 during the training period.
- w (t) [w 1 (t), ⁇ , w n (t)] terminal 1012 1 as a, ... it is output to 1012 n.
- FIG. 5 shows an example of the configuration of the multiband RF signal generator 1002.
- the multiband RF signal generator 1002 includes transmission blocks 1221 1 ,..., 1221 n for each band, and an RF signal synthesizer 1204.
- the frequency converter 1203 j includes at least a mixer 1211 j and a local oscillation (LO) signal generator 1212 j .
- LO local oscillation
- Digital baseband signal of the band j that is input to the terminal 1012 j w j (t) is a digital - the analog converter 1201 j is converted to an analog baseband signal is output to the low pass filter 1202 j.
- the low-pass filter 1202 j removes unnecessary high-frequency components from the input analog baseband signal and outputs them to the frequency converter 1203 j .
- the LO signal generator 1212 j outputs an LO signal composed of the carrier frequency f cj of the band j.
- the mixer 1211 j mixes the input analog baseband signal and the LO signal to generate and output an RF signal x j (t).
- Transmission block 1221 1 of each band, ⁇ ⁇ ⁇ , RF signals respectively outputted from the 1221 n x 1 (t), ⁇ , x n (t) is synthesized in the RF signal combiner 1204, to the terminal 1013 Output simultaneously.
- the baseband signal u (t) output to the terminal 1015 is input to the predistortion unit 1001.
- FIG. 6 shows an example of the configuration of the demodulator 1004.
- the demodulator 1004 includes at least a variable bandpass filter 1301, a variable frequency converter 1302, a variable lowpass filter 1303, and an analog-digital converter 1304.
- RF signals y 1 (t),..., Y n (t) of the respective bands output from the power amplifier 1003 are simultaneously input to the input terminal 1014 of the demodulator 1004.
- the demodulator 1004 selects one band j from the bands 1,..., N and demodulates only the RF signal y j (t) of the band j.
- the variable bandpass filter 1301 can freely change the passband.
- the variable band pass filter 1301 sets the pass band to band j, passes only the RF signal y j (t) of band j, and outputs it to the variable frequency converter 1302.
- the variable frequency converter 1302 includes at least a mixer 1311 and a frequency variable LO signal generator 1312.
- the frequency variable LO signal generator 1312 can freely change the frequency of the output LO signal.
- the frequency variable LO signal generator 1312 outputs the LO signal of band j (frequency f cj ) to the mixer 1311.
- the mixer 1311 mixes the input RF signal y j (t) and LO signal (frequency f cj ) of the band j , converts the RF signal y j (t) into an analog baseband signal, and outputs the analog baseband signal to the variable low-pass filter 1303. Output.
- the variable low-pass filter 1303 can freely change the cutoff frequency.
- the cutoff frequency of the variable low-pass filter 1303 is set according to the bandwidth of the analog baseband signal of each band.
- the variable low-pass filter 1303 removes unnecessary high-frequency components from the input analog baseband signal and outputs them to the analog-digital converter 1304.
- the analog-digital converter 1304 converts the input analog baseband signal into a digital baseband signal u j (t) of band j, and outputs it to the terminal 1015.
- the digital baseband signal u j (t) output to the terminal 1015 is input to the predistortion unit 1001.
- the demodulation of the RF signal y j (t) of the band j by the demodulator 1004 and the input of the digital baseband signal u j (t) to the predistortion unit 1001 are completed.
- the RF signal y k (t) of the band k different from the band j is demodulated, and the digital baseband signal u k (t) is input to the predistortion unit 1001.
- FIG. 7 shows an example of another configuration of the demodulator 1004.
- the demodulator 1004 shown in FIG. 7 includes demodulation blocks 1321 1 ,..., 1321 n for each band.
- RF signals y 1 (t),..., Y n (t) of the respective bands output from the power amplifier 1003 are simultaneously input to the input terminal 1014 of the demodulator 1004.
- Pass band of the band-pass filter 1301 j included in the demodulation block 1321 j band j is configured to pass only RF signals y j band j (t).
- the RF signal y j (t) that has passed through the bandpass filter 1301 j is input to the frequency converter 1302 j .
- the frequency converter 1302 j includes at least a mixer 1311 j and an LO signal generator 1312 j .
- the LO signal generator 1312 j outputs the LO signal of band j (frequency f cj ) to the mixer 1311.
- the mixer 1311 mixes the input RF signal y j (t) and LO signal (frequency f cj ) of the band j , converts the RF signal y j (t) into an analog baseband signal, and outputs the analog baseband signal to the low-pass filter 1303 j . Output.
- the cutoff frequency of the low pass filter 1303 j is designed according to the bandwidth of the analog baseband signal of each band.
- the low-pass filter 1303 j removes unnecessary high-frequency components from the input analog baseband signal and outputs the analog baseband signal to the analog-digital converter 1304 j .
- the analog-digital converter 1304 j converts the input analog baseband signal into a digital baseband signal u j (t) of band j, and outputs it to the terminal 1015 j .
- the digital baseband signal u j (t) output to the terminal 1015 j is input to the predistortion unit 1001. Terminal 1015 1, ..., each of the 1015 n baseband signals u 1 (t), ⁇ , u n (t) is output.
- delay times ⁇ DM1 ,..., ⁇ DMn are delay times in bands 1 ,.
- the entire path delay correction unit 1103 includes variable delay means 1103 1 ,..., 1103 n .
- the delay amount ⁇ 1 is the sum of delays in the multiband RF signal generator 1002 and the demodulator 1004 and can be expressed as follows.
- the variable delay means 1103 1 ,..., 1103 n can be implemented by a digital filter, for example.
- the delay amounts ⁇ 1 ,..., ⁇ n of each band in the path from the input terminals 1012 1 ,..., 1012 n of the multiband RF signal generator 1002 to the output terminal 1015 of the demodulator 1004 are as follows: It can be obtained by.
- the baseband signal z d (t) output from the entire path delay correction unit 1103 and the baseband signal u (t) output from the demodulator 1004 are input to the distortion characteristic calculation unit 1104 included in the predistortion unit 1001. Entered.
- the delay amount of z i (t ⁇ i ) and u i (t) is calculated from the correlation function.
- the distortion characteristic calculation unit 1104 then delays ⁇ i of the variable delay means 1103 i in the entire path delay correction unit 1103 so that the delay difference between z i (t ⁇ i ) and u i (t) is minimized.
- the distortion characteristic calculation unit 1104 calculates the complex amplitudes [b x1 (t ⁇ DM1 ),... xn (t ⁇ DMn )], [b y1 (t ⁇ DM1 ),..., b yn (t ⁇ DMn )], based on measurement data h 1 , ⁇ to determine the h n.
- the determined functions h 1 ,..., H n are sent from the distortion characteristic calculation unit 1104 to the distortion compensation control signal generation unit 1102.
- the distortion characteristic calculation unit 1104 can be implemented by a DSP (Digital Signal Processor) or an FPGA (Field Programmable Gate Array).
- the function h 1, ⁇ ⁇ ⁇ , h n look-up table for determining (Look-up Table: LUT) or it can be configured to include the function of polynomial fitting.
- the variable delay means 1101 1 ,..., 1101 n included in the transmitter delay correction unit 1101 can be implemented by a digital filter, for example.
- the distortion compensation control signal generation unit 1102 in the present embodiment is configured with a digital circuit implemented by a DSP or FPGA.
- the multiband RF signal y (t) output to the terminal 1014 is used for transmission.
- the complex amplitude b y (t) of the RF signal y (t) output to the terminal 1014 is given by Expression (10) as in the case of the first embodiment. Therefore, the original baseband signal z (t) input to the transmitter is carried and transmitted to the RF output signal y (t) of the power amplifier 1003 without distortion.
- the wireless transmission device 2000 operates separately in the training period and the transmission period.
- the training operation may be performed during the transmission period. That is, at the same time while communicating with another communication apparatus using a RF output signal y (t) from the power amplifier 1003, distortion compensation function h 1 performs the training operation in the radio transmitting apparatus within 2000, ..., and h n It may be determined.
- the entire path delay correction unit 1103, the distortion characteristic calculation unit 1104, and the demodulator 1004 are not used during a period when the training operation is not performed, these blocks can be in a non-operating (off) state.
- the transmitter delay correction unit 1101 appropriately sets the synchronization of the signals of the respective bands input to the power amplifier 1003.
- the RF output signal of the power amplifier 1003 is not distorted without distorting the baseband signal z (t). Transmission can be performed by transporting it to y (t).
- the predistortion unit 1001 is mounted using a digital circuit. However, a part of the configuration of the predistortion unit 1001 may be mounted using an analog circuit.
- variable delay means 1101 1 included in the transmitter delay correction unit 1101, ..., 1101 the variable delay means 1103 1 n, and the entire path delay correction unit 1103 comprises, ..., 1103 n is place of the digital filter It is good also as mounting in an analog filter.
- each band j included in the distortion compensation control signal generation unit 1102 (j 1, ⁇ , n) distortion compensation control signal generation unit 1102 j corresponding to the digital circuit implemented using a DSP or FPGA Instead, it may be implemented using an analog circuit as shown in FIG. As shown in FIG. 8, the distortion compensation control signal generation unit 1102 j using an analog circuit includes at least an analog multiplier 1601 j , a variable gain amplifier row 1602 j , and a baseband signal adder 1603 j .
- the distortion compensation control signal generation unit 1102 j is terminal 1021 j1, ⁇ ⁇ ⁇ , signal input to the 1021 jn [v j1 (t) , ⁇ , v jn (t)] with respect to the formula (14 ) and outputs a given signal w j (t) to the terminal 1012 j in.
- the signals [v j1 (t),..., V jn (t)] input to the terminals 1021 j1 ,. j1 (t) ⁇ k1 ... ⁇ v jn (t) ⁇ kn (k1,..., kn are natural numbers) are generated and output to the variable gain amplifier array 1602 j .
- the variable gain amplifier row 1602 j amplifies the input signal ⁇ v j1 (t) ⁇ k1 ... ⁇ V jn (t) ⁇ kn with a gain corresponding to the coefficient a k1.
- the gain a k1... Kn of the variable gain amplifier row 1602 j is variable, and is set by information of the distortion compensation function h j output from the distortion characteristic calculation unit 1104, that is, a polynomial coefficient.
- the baseband signal adder 1603 j can be configured by an analog circuit using an operational amplifier, for example.
- the baseband signal input to the distortion compensation control signal generation unit 1102 j may be divided into an in-phase component (In-phase signal) and a quadrature component (Quadrature signal).
- the distortion compensation control signal generation unit 1102 j may be provided with two analog circuit configurations shown in FIG. 8 and used for the in-phase component and the quadrature component, respectively.
- the frequency converter 1203 j included in the multiband RF signal generator 1002 can be configured to include a quadrature modulator.
- the transmitter delay correction unit 1101, the distortion compensation control signal generation unit 1102, and the entire path correction unit 1103 included in the predistortion unit 1001 may be mounted using an analog circuit.
- the path from the terminals 1011 1 ,..., 1011 n to the input terminal 1013 of the power amplifier 1003 is configured by an analog circuit. Therefore, the digital-analog converters 1201 1 ,..., 1201 n included in the multiband RF signal generator 1002 are not necessary, and the number of components can be reduced.
- Multiband RF signal generator delays in 1002 time tau TX1, ..., the leading cause of tau TXn shown in FIG. 5, a low pass filter 1202 1, ..., a 1202 n. Therefore, the delay times of the low-pass filters 1202 1 ,..., 1202 n can be regarded as the delay times ⁇ TX1 ,.
- the low-pass filter 1202 1, ..., 1202 delay detector 1701 1 for detecting the delay time of n, ..., add 1701 n Can be configured.
- the delay times detected by the delay detectors 1701 1 ,..., 1701 n may be the delay times ⁇ TX1 ,..., ⁇ TXn of the multiband RF signal generator 1002.
- Delay detector 1701 1, ⁇ ⁇ ⁇ , 1701 n and LPF 1202 1, ⁇ ⁇ ⁇ , 1202 n delay time of the low-pass filter from the input signal and the output signal of tau TX1, ⁇ ⁇ ⁇ , to detect tau TXn.
- the low-pass filter 1202 1, ..., 1202 the input signal of the n terminals 1702 1,..., 1702 n via the delay detector 1701 1, ..., are input to the 1701 n, the output signal terminal 1703 1 ,..., 1703 n are input.
- Detected delay time tau TX1, ..., signals representative of tau TXn has terminals 1704 1, ..., via the 1704 n are sent to the transmitter delay correction unit 1101, the transmitter delay correction unit 1101 Variable delay means 1101 provided is used for setting a delay time in kj (k, j 1,..., N).
- the delay detector 1701 j includes at least analog-digital converters 1802 j and 1803 j and a correlation function calculator 1801 j .
- the analog-digital converters 1802 j and 1803 j convert the input / output signals of the low-pass filter 1202 j input from the terminals 1702 j and 1703 j into digital signals and output them to the correlation function calculator 1801 j .
- the correlation function calculator 1801 j calculates the correlation function from the input / output signal of the input low-pass filter 1202 j , and calculates the delay time ⁇ TXj of the low-pass filter 1202 j from this correlation function.
- the correlation function calculator 1801 j has a function of calculating a correlation function of two input signals, and can be configured by a digital circuit implemented using a DSP or FPGA. In this case, without using an external measuring device such as an oscilloscope, the delay detector 1701 1 incorporated in the radio transmitting apparatus 2000, ..., 1701 the delay time by n tau TX1, ..., a tau TXn It can be automatically detected.
- FIG. 11 is a block diagram illustrating a configuration of the wireless transmission device 3000 according to the present embodiment.
- the wireless transmission device 3000 includes at least a predistortion unit 1001A, a multiband RF signal generator 1002D, a power amplifier 1003, and a demodulator 1004.
- the predistortion unit 1001A includes at least a transmitter delay correction unit 1101A, a distortion compensation control signal generation unit 1102A, an entire path delay correction unit 1103, and a distortion characteristic calculation unit 1104.
- the multiband RF signal generator 1002D includes at least a multiband transmission block 1002A, an RF signal phase corrector 1501, an RF signal gain corrector 1502, and an RF signal synthesizer 1204.
- the wireless transmission device 3000 transmits RF signals of a plurality of bands at the same time as the wireless transmission devices 1000 and 2000 according to the first and second embodiments described above. Based on the nonlinear characteristic of the power amplifier 1003 specified during the training period, distortion compensation of the RF output signal of the power amplifier 1003 is performed during the transmission period.
- n-number of base band signal z (t) [z 1 (t), ⁇ , z n (t)] is the terminal 1011 1, ..., are input to the 1011 n .
- FIG. 12 shows an example of the configuration of the multiband transmission block 1002A.
- the multiband transmission block 1002A has the same configuration as the multiband RF signal generator 1002 shown in FIG. 5 except for the RF signal synthesizer 1204.
- the frequency-converted RF signals are output to the terminals 1503 1 ,..., 1503 n without being synthesized.
- the RF signals q 1 (t),..., Q n (t) of the bands 1,. Is input to the device 1501.
- the RF signal phase corrector 1501 includes n RF signal phase correctors 1501 1 ,..., 1501 n, and RF signals q 1 (t),. ..., and outputs the added phase shift of the specified amount q n (t).
- the input RF signal is output to the RF signal gain corrector 1502 as it is without adding a phase shift to the input RF signal.
- the RF signal gain corrector 1502 includes n RF signal gain correctors 1502 1 ,..., 1502 n , and a specified amount of gain change is applied to the input RF signals of band 1,. Is added and output. During the training period, the input RF signal is output to the RF signal synthesizer 1204 as it is without adding a gain change to the input RF signal.
- the RF signal synthesizer 1204 synthesizes the RF signals x 1 (t),..., X n (t) of the band 1,. Simultaneously output to the input terminal 1013 of 1003.
- the baseband signal u (t) is input to the predistortion unit 1001A.
- the method by which the distortion characteristic calculation unit 1104 calculates the distortion compensation functions h 1 ,..., H n is the same as the calculation method in the second embodiment, and a description thereof will be omitted.
- the transmitter delay correction unit 1101A and the distortion compensation control signal generation unit 1102A included in the predistortion unit 1001A may be in a non-operating state (off state).
- the complex amplitude b x (t) [b x1 (t),..., B xn (t)] of the RF signal to be input to the power amplifier 1003 during the transmission period is as described in the first embodiment. Is given by equation (8).
- an RF signal having a complex amplitude represented by Expression (8) is input to the power amplifier 1003
- the complex amplitude b y (t) of the RF signal output from the power amplifier 1003 indicates the nonlinearity g of the power amplifier 1003. The effect is removed.
- the original baseband signal z (t) input to the wireless transmission device 3000 is conveyed and transmitted to the RF output signal of the power amplifier 1003 without distortion.
- the RF signal gain corrector 1502 1, ..., gain variation .DELTA.G 1 in 1502 n, ..., .DELTA.G n and RF signal phase corrector 1501 1, ..., a phase change amount ⁇ in 1501 n 1 ,..., ⁇ n are set to the ratio of each component of the complex amplitude b x (t) in Equation (15) and Equation (16). That is, the gain change amounts ⁇ G 1 ,..., ⁇ G n are set as shown in the following equation (17).
- ⁇ G 1
- ⁇ G n
- , Further, the phase change amounts ⁇ 1 ,..., ⁇ n are set as shown in the following equation (18).
- the RF signal phase corrector 1501 and the RF signal gain corrector 1502 are configured so that the distortion compensation functions h 1 ,..., H n and the signal [z 1 (t ⁇ TX1 ),..., z n (t ⁇ TXn )] need to be dynamically controlled. Such control will be described below.
- the distortion compensation control signal generation unit 1102A stores information on distortion compensation functions h 1 ,..., H n generated during training.
- the signal [z 1 (t ⁇ TX1 ),..., Z n (t ⁇ TXn )] is received and is output to the distortion compensation control signal generation unit 1102A.
- the distortion compensation control signal generation unit 1102A is generated during training with the signals [z 1 (t ⁇ TX1 ),..., Z n (t ⁇ TXn )] input from the transmitter delay correction unit 1101A.
- Information on distortion compensation functions h 1 ,..., H n is acquired. Based on these pieces of information, the distortion compensation control signal generator 1102A controls the RF signal phase corrector 1501 and the RF signal gain corrector 1502 so as to obtain the characteristics shown in the equations (17) and (18). I do. By such control, linearization of the power amplifier 1003 is achieved.
- variable delay means 1101A 1 ,..., 1101A n included in the transmitter delay correction unit 1101A can be implemented using a digital filter.
- the distortion compensation control signal generation unit 1102A is a digital circuit implemented using a DSP or FPGA.
- the RF signal phase corrector is based on the baseband signal output from the transmitter delay correction unit 1101A and the functions h 1 ,..., H n according to the equations (17) and (18). 1501 and a control signal for the RF signal gain corrector 1502 are output.
- the entire path delay correction unit 1103, the distortion characteristic calculation unit 1104, and the demodulator 1004 included in the wireless transmission device 3000 are not used, so that these blocks are not operated (off state). Also good.
- the operation of the wireless transmission device 3000 according to the present embodiment has been described separately for the training period and the transmission period.
- the training operation may be performed during the transmission period. That is, the distortion compensation function h 1 ,..., H n is performed by performing a training operation in the wireless transmission device 3000 at the same time while communicating with other communication devices using the output signal y (t) from the power amplifier 1003. May be determined.
- the transmitter delay correction unit 1101A appropriately sets the synchronization of the signals of each band input to the power amplifier 1003.
- the RF output signal y (t) of the power amplifier 1003 is not distorted without distorting the baseband signal z (t). Can be transported and transmitted.
- a part of the configuration of the predistortion unit 1001A may be mounted with an analog circuit.
- variable delay means 1101A 1 ,..., 1101A n included in transmitter delay correction section 1101A and variable delay means 1103 1 ,..., 1103 n included in entire path delay correction section 1103 are replaced with digital filters. You may mount with an analog filter.
- a low pass filter 1202 1, ⁇ ⁇ ⁇ , 1202 n delay detector 1701 detects a delay time of 1 ,..., 1701 n can be added.
- the delay times detected by the delay detectors 1701 1 ,..., 1701 n can be regarded as the delay times ⁇ TX1 ,..., ⁇ TXn in the multiband RF signal generator 1002D.
- FIG. 13 is a block diagram illustrating a configuration of the wireless transmission device 4000 according to the present embodiment.
- the wireless transmission device 4000 includes at least a predistortion unit 1001A, a multiband RF signal generator 1002E, a power amplifier 1003, and a demodulator 1004.
- the multiband RF signal generator 1002E includes at least a multiband transmitter baseband unit 1002B, a baseband signal phase corrector 1501B, a baseband signal gain corrector 1502B, and a multiband transmitter RF unit 1002C.
- FIG. 14 shows an example of the configuration of the multiband transmitter baseband unit 1002B.
- the multiband transmitter baseband unit 1002B includes transmission block baseband units 1221B 1 ,..., 1221B n for each band.
- the components z 1 (t),..., Z n (t) of the baseband signal z (t) are input to the terminals 1012 1 ,..., 1012 n of the multiband transmitter baseband unit 1002B, respectively. .
- Digital baseband signal of the band j that is input to the terminal 1012 j z j (t) is a digital - after being converted into an analog baseband signal in the analog converter 1201 j, is output to the low pass filter 1202 j.
- the low-pass filter 1202 j removes unnecessary high-frequency components from the input analog baseband signal and outputs the analog baseband signal p j (t) to the terminal 1511 j .
- the analog baseband signals p 1 (t),..., P n (t) of the bands 1,..., Band n output from the multiband transmitter baseband unit 1002B are Each is input to the baseband signal phase corrector 1501B.
- the baseband signal phase corrector 1501B includes n baseband signal phase correctors 1501B 1 ,..., 1501B n, and analog baseband signals p 1 of band 1,. Outputs (t), ..., p n (t) with a specified amount of phase shift added.
- the baseband signal gain corrector 1502B includes n baseband signal gain correctors 1502B 1 ,..., 1502B n .
- FIG. 15 shows an example of the configuration of the multiband transmitter RF unit 1002C.
- the multiband transmitter RF unit 1002C includes at least frequency converters 1203 1 ,..., 1203 n for each band and an RF signal synthesizer 1204.
- the frequency converter 1203 j includes an LO signal generator 1212 j and a mixer 1211 j .
- the LO signal generator 1212 j outputs an LO signal having a carrier frequency f cj of band j.
- the mixer 1211 j generates and outputs an RF signal x j (t) by mixing the input analog baseband signal r j (t) and the LO signal.
- the RF signal phase corrector 1501 and the RF signal gain corrector 1502 are configured to correct the gain and phase of the RF signal.
- the baseband signal phase corrector 1501B and the baseband signal gain corrector 1502B are configured to correct the gain and phase of the baseband signal. It was. That is, the difference between the wireless transmission device 4000 (FIG. 13) according to the present embodiment and the wireless transmission device 3000 (FIG. 11) of the third embodiment is that the signal for gain and phase correction is an RF signal. Or it is only a point whether it is a baseband signal. Other configurations are common to both.
- the wireless transmission device 4000 transmits RF signals of a plurality of bands simultaneously, and based on the nonlinear characteristics of the power amplifier 1003 specified during the training period, distortion compensation of the RF output signal of the power amplifier 1003 during the transmission period. I do.
- the wireless transmission device 4000 measures the input / output characteristics of the power amplifier 1003 during the training period and calculates distortion compensation functions h 1 ,..., H n by the same procedure as the wireless transmission device 3000 of the third embodiment. .
- the operation of the wireless transmission device 4000 in the transmission period is the same as the operation of the wireless transmission device 3000 of the third embodiment.
- baseband signals phase corrector 1501B and the baseband signal gain corrector 1502B is inputted baseband signal p 1 (t), ⁇ ⁇ ⁇ , equation (17) with respect to p n (t) and ( The gain correction amount and the phase correction amount given in 18) are given.
- the transmitter delay correction unit 1101A appropriately sets the synchronization of the signals of each band input to the power amplifier 1003.
- the RF output signal y (t) of the power amplifier 1003 is not distorted without distorting the baseband signal z (t). Can be transported and transmitted.
- a part of the configuration of the predistortion unit 1001A may be mounted with an analog circuit.
- the multiband transmitter baseband unit 1002B detects the delay times of the low-pass filters 1202 1 ,..., 1202 n.
- the delay detectors 1701 1 ,..., 1701 n to be added may be added.
- the delay times detected by the delay detectors 1701 1 ,..., 1701 n can be regarded as the delay times ⁇ TX1 ,..., ⁇ TXn of the multiband RF signal generator 1002E.
- the wireless transmission device has the following advantages over the related wireless transmission device described in Patent Document 2 described in the background art.
- the wireless transmission device includes a transmitter delay correction unit. Therefore, it is possible to correct a synchronization shift between bands of the input signal of the power amplifier, which is caused by a delay time in a path from the distortion compensation control signal generation unit to the input terminal of the power amplifier. As a result, it is possible to solve the problem of distortion degradation caused by synchronization loss and to transmit signals without distortion even when a power amplifier having nonlinear input / output characteristics is used.
- a multiband RF signal generator for carrying a plurality of input baseband signals on carrier waves of different frequencies and outputting them as radio frequency signals;
- a power amplifier for amplifying and outputting the radio frequency signal;
- a distortion compensation control signal generation unit that applies a distortion compensation function for compensating distortion characteristics of the power amplifier to the plurality of input baseband signals;
- a transmitter delay correction unit configured to correct a difference in delay time received by each of the plurality of input baseband signals in the multiband RF signal generator.
- the demodulator converts the radio frequency signal output from the power amplifier into an output baseband signal for each frequency band of a carrier wave
- the entire path delay correction unit corresponds to the entire path delay time for each frequency band of the carrier wave in the path from the output of the distortion compensation control signal generation unit to the output of the demodulator, and the plurality of input baseband signals. Add delay time correction every time, The distortion characteristic calculation unit is based on the plurality of input baseband signals subjected to delay time correction output from the entire path delay correction unit and the plurality of output baseband signals output from the demodulator.
- the distortion characteristic calculation unit calculates a correlation function between the input baseband signal and the output baseband signal, calculates the entire path delay time based on the correlation function, and based on the calculated total path delay time.
- amendment part branches the input baseband signal conveyed by the one said carrier wave into the number of the said different frequency, and gives delay time to the said branched input baseband signal, respectively.
- Each of the delay times is a delay that an input baseband signal carried by the one carrier receives in the multiband RF signal generator, and an input baseband signal carried by another carrier is the multiband RF signal generator.
- the wireless transmission device according to appendix 1 or 2, which is a difference from a delay received in step 1.
- the multiband RF signal generator includes at least a plurality of low-pass filters, a plurality of frequency converters, and an RF signal synthesizer,
- the low-pass filter removes a high-frequency component of the baseband signal input from the distortion compensation control signal generation unit
- the frequency converter carries the baseband signal output from the low-pass filter into a radio frequency signal in a frequency band of a carrier wave and outputs it, 4.
- the radio transmission apparatus according to claim 1, wherein the RF signal synthesizer synthesizes and outputs each radio frequency signal in the frequency band of the carrier wave output from the plurality of frequency converters. 5.
- the multiband RF signal generator is A plurality of low-pass filters for removing high-frequency components of the plurality of input baseband signals; A plurality of frequency converters for outputting the plurality of input baseband signals output from the low-pass filter to radio frequency signals in a carrier frequency band; A plurality of RF signal phase correctors that respectively correct the phases of the radio frequency signals output from the frequency converter; A plurality of RF signal gain correctors that respectively correct the gain of the radio frequency signal output from the frequency converter; An RF signal synthesizer that synthesizes and outputs the radio frequency signal whose gain and phase have been corrected in the gain corrector and the phase corrector, and The distortion compensation control signal generation unit generates a corrected baseband signal obtained by applying a distortion compensation function for compensating a distortion characteristic of the power amplifier to the plurality of input baseband signals, and a carrier wave carrying the corrected baseband signal Supplementary note 1 or 2 for controlling a gain correction amount in the RF signal gain corrector and a phase correction amount in
- the multiband RF signal generator is A plurality of low-pass filters for removing high-frequency components of the plurality of input baseband signals; A plurality of baseband signal phase correctors that respectively correct the phases of the plurality of input baseband signals output from the low-pass filter; A plurality of baseband signal gain correctors that respectively correct the gains of the plurality of input baseband signals output from the low-pass filter; A plurality of frequency converters that respectively output the plurality of input baseband signals output from the baseband signal phase corrector and the baseband signal gain corrector to a radio frequency signal in a frequency band of a carrier; An RF signal synthesizer that synthesizes and outputs the radio frequency signals respectively output from the frequency converter,
- the distortion compensation control signal generation unit generates a corrected baseband signal obtained by applying a distortion compensation function for compensating a distortion characteristic of the power amplifier to the plurality of input baseband signals, and a carrier wave that carries the corrected baseband signal Supplementary note 1 for controlling a gain correction amount in the baseband
- the multiband RF signal generator further includes a delay detector that detects a delay time of the low-pass filter, The delay detector sends the detected delay time of the low-pass filter to the transmitter delay correction unit, The transmitter delay correction unit corrects the delay time of the low-pass filter as a difference in delay received by each of the plurality of input baseband signals in the multiband RF signal generator.
- the amplified radio frequency signal is converted into an output baseband signal for each frequency band of a carrier wave, Calculating a correlation function between the input baseband signal and the output baseband signal; Based on the correlation function, an overall path delay time, which is a delay time received from when the input baseband signal is subjected to the distortion compensation function to being converted into the output baseband signal, is calculated. Based on the overall path delay time, correct the difference in delay time for each input baseband signal, The wireless transmission method according to appendix 8, wherein the distortion compensation function is calculated for each frequency band of the carrier wave based on the input baseband signal and the output baseband signal that have been corrected for the delay time difference.
- the demodulator A variable bandpass filter that can change the passband and pass only radio frequency signals in the specified carrier frequency band, A variable frequency converter for converting a radio frequency signal of the designated carrier frequency band into an analog baseband signal; A variable low-pass filter that can change a cutoff frequency and removes a high frequency from the analog baseband signal output from the variable frequency converter; An analog-to-digital converter that converts an analog baseband signal output from the variable low-pass filter into a digital signal, Of the radio frequency signals of the plurality of carrier frequency bands output from the power amplifier, only the radio frequency signal of the designated carrier frequency band is converted into a baseband signal and output to the distortion characteristic calculation unit.
- Appendix 2 for outputting baseband signals in a plurality of carrier frequency bands to the distortion characteristic calculation unit by switching radio frequency signals in different carrier frequency bands to respective baseband signals by switching the frequency bands of the carrier waves The wireless transmission device described.
- the demodulator A plurality of bandpass filters that pass only radio frequency signals in the frequency band of each carrier; A plurality of frequency converters for converting each radio frequency signal in the frequency band of each carrier into an analog baseband signal; A plurality of low-pass filters for removing high frequencies from the analog baseband signal output from the frequency converter of the frequency band of each carrier; An analog-to-digital converter that converts an analog baseband signal output from the low-pass filter of each carrier frequency band into a digital signal, and
- the radio transmission apparatus according to appendix 2, wherein radio frequency signals in a plurality of carrier frequency bands output from the power amplifier are converted into baseband signals in the respective carrier frequency bands and output to the distortion characteristic calculation unit.
- the delay detector is: An analog-to-digital converter that converts the input signal and output signal of the low-pass filter into digital signals, A correlation function calculator that calculates a correlation function of the input signal and the output signal of the low-pass filter, The wireless transmission device according to appendix 7, wherein the correlation function calculator calculates a delay time in the low-pass filter based on the correlation function.
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Abstract
Description
図1は、本発明の第1の実施形態に係る無線送信装置の構成を示すブロック図である。本実施形態による無線送信装置1000は、送信機遅延補正部1101、歪補償制御信号生成部1102、マルチバンドRF信号発生器1002、および電力増幅器1003を少なくとも有する。上記構成において、特に、送信機遅延補正部1101が本実施形態による無線送信装置1000の特徴的な構成である。
bx(t)=[bx1(t),・・・,bxn(t)]=[z1(t-τTX1),・・・, zn(t-τTXn)] (1)
ここで、式(1)の右辺をzin(t)=[z1(t-τTX1),・・・,zn(t-τTXn)]と定義する。
by1(t)=g1[bx1(t),・・・,bxn(t)],
・・・, (2)
byn(t)=gn[bx1(t),・・・,bxn(t)],
これは背景技術で説明したように、複数のバンドの信号を同時に送信する場合、送信機の非線形性による周波数ミキシング効果が生じるため、RF出力信号の各バンドにおける成分は送信機に入力される全てのバンドのベースバンド信号に依存するからである。ここでg1,・・・,gnはn個の変数bx1(t),・・・,bxn(t)を引数とした非線形の関数であり、電力増幅器1003の各バンドにおける入出力特性の非線形性を表している。
by(t)=g[bx(t)] (3)
ここでgは非線形写像であり、関数g1,・・・,gnをまとめて表記したものである。
bx1(t)=h1[by1(t),・・・,byn(t)],
・・・, (4)
bxn(t)=hn[by1(t),・・・,byn(t)],
ここで、h1,・・・,hnはn個の変数by1(t),・・・,byn(t)を引数とした非線形の関数である。式(4)と同じ内容は下記の式(5)によっても表わすことができる。
bx(t)=h[by(t)] (5)
ここでhは非線形写像であり、関数h1,・・・,hnをまとめて表記したものである。式(3)の非線形写像gと式(5)の非線形写像hはお互いに逆写像の関係にある。
τkj = τTXj-τTXk+τC (k,j=1,・・・,n) (6)
ここでτCは定数の遅延時間であり、任意の値に取ることができる。ただし、実装する遅延時間τkj (k,j=1,・・・,n)は非負でなければならないという条件から、τC=Max(|τTXj-τTXk|)とするのが望ましい。ここで、「Max」は最大値を表わす。
w1(t) = h1[v11(t),・・・,v1n(t)] = h1[z1(t-τ11),・・・,zn(t-τ1n)],
・・・, (7)
wn(t) = hn[vn1(t),・・・,vnn(t)] = hn[z1(t-τn1),・・・,zn(t-τnn)],
マルチバンドRF信号発生器1002は、トレーニング期間と同様に送信期間においても、端子10121,・・・,1012nから入力されたベースバンド信号w(t)の各成分w1(t),・・・,wn(t)を、それぞれバンド1,・・・,バンドnのキャリア周波数に周波数変換する。そしてRF信号x(t)=[x1(t),・・・,xn(t)]を生成し、端子1013に出力する。
bx1(t) = w1(t-τTX1) = h1[z1(t-(τTX1+τC)),・・・,zn(t-(τTXn+τC))],
・・・, (8)
bxn(t) = wn(t-τTXn) = hn[z1(t-(τTX1+τC)),・・・,zn(t-(τTXn+τC))],
ここで、式(1)の右辺で定義したトレーニング時の電力増幅器1003のRF入力信号の複素振幅zin(t)= [z1(t-τTX1),・・・,zn(t-τTXn)]を用いると、式(8)は下記の式(9)のようにまとめることができる。
bx(t)=h[zin(t-τC)] (9)
式(9)の複素振幅bx(t)を持つRF信号x(t)が電力増幅器1003に入力され、複素振幅by(t)を有するRF信号y(t)が電力増幅器1003から端子1014に出力される。この端子1014に出力されたマルチバンドのRF信号y(t)が送信に用いられる。
by(t) = g[bx(t)] = g・h[zin(t-τC)] = zin(t-τC) (10)
式(10)において、非線形写像gとhは互いに逆写像であるため打ち消しあっている。すなわち式(10)から、本実施形態による無線送信装置1000においては、電力増幅器1003から出力されるRF信号の複素振幅by(t)から電力増幅器1003の非線形性gの影響が取り除かれていることがわかる。その結果、無線送信装置1000に入力された元のベースバンド信号z(t)は歪むことなく電力増幅器1003のRF出力信号に搬送されて送信される。つまり、本実施形態の無線送信装置によれば、複数の経路における遅延時間の差に起因して生じる出力信号における歪量の増大を抑制することができる。
w1(t) = h1[z1(t),・・・,zn(t)],
・・・, (11)
wn(t) = hn[z1(t),・・・,zn(t)],
マルチバンドRF信号発生器1002は、端子10121,・・・,1012nから入力されたベースバンド信号w(t)の各成分w1(t),・・・,wn(t)を、それぞれバンド1,・・・,バンドnのキャリア周波数に周波数変換したRF信号x(t)=[x1(t),・・・,xn(t)]を生成し、端子1013に出力する。電力増幅器1003に入力されるRF信号の複素振幅bx(t)=[bx1(t),・・・,bxn(t)]は、マルチバンドRF信号発生器1002におけるバンド1,・・・,nの遅延時間τTX1,・・・,τTXnによって、下記の式(12)で表される波形になる。
bx1(t) = w1(t-τTX1) = h1[z1(t-τTX1),・・・,zn(t-τTX1)],
・・・, (12)
bxn(t) = wn(t-τTXn) = hn[z1(t-τTXn),・・・,zn(t-τTXn)],
この場合、関数h1の引数はz(t-τTX1)=[z1(t-τTX1),・・・,zn(t-τTX1)],・・・,であり、関数hnの引数はz(t-τTXn)=[z1(t-τTXn),・・・,zn(t-τTXn)]となる。式(12)のように関数h1,・・・, hnに異なる引数を代入して生成される複素振幅bx(t)を持つRF信号を電力増幅器1003に入力した場合、電力増幅器1003のRF出力信号から電力増幅器1003の非線形性gの影響を除くことはできない。その理由は以下の通りである。
次に、本発明の第2の実施形態について説明する。図4は、本実施形態に係る無線送信装置2000の構成を示すブロック図である。無線送信装置2000は、プリディストーション部1001、マルチバンドRF信号発生器1002、電力増幅器1003、および復調器1004を有する。ここでプリディストーション部1001は、送信機遅延補正部1101、歪補償制御信号生成部1102、全体経路遅延補正部1103、および歪特性演算部1104を備える。
u(t)=[u1(t),・・・,un(t)]=[by1(t-τDM1),・・・, byn(t-τDMn)] (13)
ここで、遅延時間τDM1,・・・,τDMnは、復調器1004でそれぞれ生じるバンド1,・・・,nにおける遅延時間である。
遅延量τ1=τTX1+τDM1,・・・,τn=τTXn+τDMn
送信機遅延補正部1101に入力されたベースバンド信号z(t)=[z1(t),・・・,zn(t)]の各成分は、全体経路遅延補正部1103が備える可変遅延手段11031,・・・,1103nによって遅延を受ける。その結果、遅延を受けたベースバンド信号zd(t)=[z1(t-τ1),・・・,zn(t-τn)]が全体経路遅延補正部1103から出力される。ここで、可変遅延手段11031,・・・,1103nは、例えばディジタルフィルタによって実装することができる。
上述の説明では、プリディストーション部1001はディジタル回路を用いて実装することとしたが、プリディストーション部1001の構成の一部をアナログ回路により実装することとしてもよい。
図5で示したマルチバンドRF信号発生器1002における遅延時間τTX1,・・・,τTXnの主要な原因は、ローパスフィルタ12021,・・・,1202nである。したがって、ローパスフィルタ12021,・・・,1202nの遅延時間をマルチバンドRF信号発生器1002における遅延時間τTX1,・・・,τTXnと見なすことができる。このとき、図9に示したマルチバンドRF信号発生器1002のように、ローパスフィルタ12021,・・・,1202nの遅延時間を検出する遅延検出器17011,・・・,1701nを追加した構成とすることができる。そして、遅延検出器17011,・・・,1701nで検出された遅延時間をマルチバンドRF信号発生器1002の遅延時間τTX1,・・・,τTXnとすればよい。
次に、本発明の第3の実施形態について説明する。図11は、本実施形態に係る無線送信装置3000の構成を示すブロック図である。無線送信装置3000は、プリディストーション部1001A、マルチバンドRF信号発生器1002D、電力増幅器1003、および復調器1004を少なくとも有する。
bx1(t) = h1[z1(t-τTX1),・・・,zn(t-τTXn)],
・・・, (15)
bxn(t) = hn[z1(t-τTX1),・・・,zn(t-τTXn)],
このように、電力増幅器1003に入力されるべきRF信号の複素振幅bx(t)=[bx1(t),・・・,bxn(t)]が式(15)によって表わすことができる理由を以下に説明する。RF信号位相補正器1501およびRF信号利得補正器1502において位相シフトおよび利得変化を加えない場合、電力増幅器1003に入力されるRF信号の複素振幅bx(t)=[bx1(t),・・・,bxn(t)]は、下記の式(16)で与えられる。
bx1(t) = z1(t-τTX1),
・・・ (16)
bxn(t) = zn(t-τTXn)
ここで、RF信号利得補正器15021,・・・,1502nにおける利得変化量ΔG1,・・・, ΔGnおよびRF信号位相補正器15011,・・・,1501nにおける位相変化量Δθ1,・・・, Δθnを、式(15)および式(16)の複素振幅bx(t)の各成分の比に設定する。すなわち、利得変化量ΔG1,・・・, ΔGnについては、下記の式(17)に示すように設定する。
ΔG1= |h1[z1(t-τTX1),・・・,zn(t-τTXn)]/z1(t-τTX1)|,
・・・, (17)
ΔGn = |hn[z1(t-τTX1),・・・,zn(t-τTXn)]/zn(t-τTXn)|,
また、位相変化量Δθ1,・・・, Δθnについては、下記の式(18)に示すように設定する。
Δθ1= ∠(h1[z1(t-τTX1),・・・,zn(t-τTXn)]/z1(t-τTX1)),
・・・, (18)
Δθn= ∠(hn[z1(t-τTX1),・・・,zn(t-τTXn)]/zn(t-τTXn)),
RF信号位相補正器1501およびRF信号利得補正器1502をこのように設定することにより、電力増幅器1003に入力されるRF信号の複素振幅bx(t)を式(16)の状態から式(15)の状態に変化させることができる。すなわち、電力増幅器1003に入力されるRF信号の複素振幅が式(15)で表わされる値に設定され、電力増幅器1003の線形化が達成される。
第2の実施形態の第1の変形例と同様に、本実施形態による無線送信装置3000においても、プリディストーション部1001Aの構成の一部をアナログ回路で実装することとしてもよい。例えば、送信機遅延補正部1101Aが備える可変遅延手段1101A1,・・・,1101Anおよび全体経路遅延補正部1103が備える可変遅延手段11031,・・・,1103nを、ディジタルフィルタに替えてアナログフィルタで実装してもよい。
第2の実施形態の第2の変形例と同様に、図12に示したマルチバンド送信ブロック1002Aにおいても、ローパスフィルタ12021,・・・,1202nの遅延時間を検出する遅延検出器17011,・・・,1701nを追加した構成とすることができる。この場合は、遅延検出器17011,・・・,1701nで検出された遅延時間をマルチバンドRF信号発生器1002Dにおける遅延時間τTX1,・・・,τTXnと見なすことができる。ここで検出された遅延時間τTX1,・・・,τTXnを表す信号は、図9の端子17041,・・・,1704nを経由して送信機遅延補正部1101Aに送信され、送信機遅延補正部1101Aが備える可変遅延手段1101Ak(k=1,・・・,n)の遅延時間の設定に用いることができる。
次に、本発明の第4の実施形態について説明する。図13は、本実施形態に係る無線送信装置4000の構成を示すブロック図である。無線送信装置4000は、プリディストーション部1001A、マルチバンドRF信号発生器1002E、電力増幅器1003、および復調器1004を少なくとも有する。マルチバンドRF信号発生器1002Eは、マルチバンド送信機ベースバンド部1002B、ベースバンド信号位相補正器1501B、ベースバンド信号利得補正器1502B、およびマルチバンド送信機RF部1002Cを少なくとも備える。
第3の実施形態の第1の変形例と同様に、本実施形態による無線送信装置4000においても、プリディストーション部1001Aの構成の一部をアナログ回路で実装することとしてもよい。
第2の実施形態の第2の変形例と同様に、図14に示した本実施形態によるマルチバンド送信機ベースバンド部1002Bにおいて、ローパスフィルタ12021,・・・,1202nの遅延時間を検出する遅延検出器17011,・・・,1701nを追加した構成としてもよい。このとき、遅延検出器17011,・・・,1701nで検出された遅延時間をマルチバンドRF信号発生器1002Eの遅延時間τTX1,・・・,τTXnと見なすことができる。検出された遅延時間τTX1,・・・,τTXnを表す信号は、端子17041,・・・,1704nを経由して送信機遅延補正部1101Aに送信され、送信機遅延補正部1101Aが備える可変遅延手段1101Ak(k=1,・・・,n)の遅延時間の設定に用いられる。
前記無線周波数信号を増幅して出力する電力増幅器と、
前記複数の入力ベースバンド信号に、前記電力増幅器の歪特性を補償する歪補償関数をそれぞれ施す歪補償制御信号生成部と、
前記マルチバンドRF信号発生器において前記複数の入力ベースバンド信号がそれぞれ受ける遅延時間の差を補正する送信機遅延補正部、とを有する
無線送信装置。
前記復調器は、前記電力増幅器から出力される前記無線周波数信号を搬送波の周波数帯域ごとに出力ベースバンド信号に変換し、
前記全体経路遅延補正部は、前記歪補償制御信号生成部の出力から前記復調器の出力までの経路における前記搬送波の周波数帯域ごとの全体経路遅延時間に対応して、前記複数の入力ベースバンド信号ごとに遅延時間の補正を加え、
前記歪特性演算部は、前記全体経路遅延補正部から出力される遅延時間の補正を受けた前記複数の入力ベースバンド信号と、前記復調器から出力される複数の前記出力ベースバンド信号とに基づいて、前記歪補償関数を前記搬送波の周波数帯域ごとに算出し、前記歪補償関数を前記歪補償制御信号生成部に受け渡し、
さらに前記歪特性演算部は、前記入力ベースバンド信号と前記出力ベースバンド信号の相関関数を算出し、前記相関関数に基づいて前記全体経路遅延時間を算出し、算出した前記全体経路遅延時間に基づいて前記全体経路遅延補正部で加える遅延時間の補正量を決定する
付記1に記載した無線送信装置。
前記遅延時間はそれぞれ、前記一の搬送波によって搬送される入力ベースバンド信号が前記マルチバンドRF信号発生器において受ける遅延と、他の搬送波によって搬送される入力ベースバンド信号が前記マルチバンドRF信号発生器において受ける遅延との差である
付記1または2に記載した無線送信装置。
前記ローパスフィルタは、前記歪補償制御信号生成部から入力されたベースバンド信号の高周波成分を除去し、
前記周波数変換器は、前記ローパスフィルタから出力された前記ベースバンド信号を搬送波の周波数帯域の無線周波数信号に搬送させて出力し、
前記RF信号合成器は、複数の前記周波数変換器から出力された前記搬送波の周波数帯域の各無線周波数信号を合成して出力する
付記1から3のいずれか一項に記載した無線送信装置。
前記複数の入力ベースバンド信号の高周波成分を除去する複数のローパスフィルタと、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力する複数の周波数変換器と、
前記周波数変換器から出力された前記無線周波数信号の位相をそれぞれ補正する複数のRF信号位相補正器と、
前記周波数変換器から出力された前記無線周波数信号の利得をそれぞれ補正する複数のRF信号利得補正器と、
前記利得補正器および位相補正器において利得と位相が補正された前記無線周波数信号を合成して出力するRF信号合成器、とを少なくとも備え、
前記歪補償制御信号生成部は、前記複数の入力ベースバンド信号に前記電力増幅器の歪特性を補償する歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号が前記マルチバンドRF信号発生器から出力するように、前記RF信号利得補正器における利得補正量および前記RF信号位相補正器における位相補正量を制御する
付記1または2に記載した無線送信装置。
前記複数の入力ベースバンド信号の高周波成分を除去する複数のローパスフィルタと、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号の位相をそれぞれ補正する複数のベースバンド信号位相補正器と、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号の利得をそれぞれ補正する複数のベースバンド信号利得補正器と、
前記ベースバンド信号位相補正器および前記ベースバンド信号利得補正器から出力された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力する複数の周波数変換器と、
前記周波数変換器からそれぞれ出力された前記無線周波数信号を合成して出力するRF信号合成器、とを少なくとも備え、
前記歪補償制御信号生成部は、前記複数の入力ベースバンド信号に前記電力増幅器の歪特性を補償する歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号が前記マルチバンドRF信号発生器から出力するように、前記ベースバンド信号利得補正器における利得補正量および前記ベースバンド信号位相補正器における位相補正量を制御する
付記1または2に記載した無線送信装置。
前記遅延検出器は、検出した前記ローパスフィルタの遅延時間を前記送信機遅延補正部に送出し、
前記送信機遅延補正部は、前記ローパスフィルタの遅延時間を、前記マルチバンドRF信号発生器において前記複数の入力ベースバンド信号がそれぞれ受ける遅延の差として補正する
付記4から6のいずれか一項に記載した無線送信装置。
前記遅延時間の差を補正された前記複数の入力ベースバンド信号に、前記無線周波数信号を増幅する際における歪特性を補償する歪補償関数をそれぞれ施す
無線送信方法。
前記入力ベースバンド信号と前記出力ベースバンド信号の相関関数を算出し、
前記相関関数に基づいて、前記入力ベースバンド信号が前記歪補償関数を施されてから前記出力ベースバンド信号に変換されるまでに受ける遅延時間である全体経路遅延時間を算出し、
前記全体経路遅延時間に基づいて、前記入力ベースバンド信号ごとに遅延時間の差を補正し、
前記遅延時間の差の補正を受けた前記入力ベースバンド信号と、前記出力ベースバンド信号とに基づいて、前記歪補償関数を前記搬送波の周波数帯域ごとに算出する
付記8に記載した無線送信方法。
一の前記搬送波によって搬送される入力ベースバンド信号を、前記異なる周波数の個数分に分岐し、前記分岐した入力ベースバンド信号にそれぞれ遅延時間を付与し、
前記遅延時間はそれぞれ、前記増幅する際に前記一の搬送波によって搬送される入力ベースバンド信号が受ける遅延と、前記増幅する際に他の搬送波によって搬送される入力ベースバンド信号が受ける遅延との差である
付記8または9に記載した無線送信方法。
通過帯域を変更でき、指定した搬送波の周波数帯域の無線周波数信号のみ通過させる可変バンドパスフィルタと、
前記指定した搬送波の周波数帯域の無線周波数信号をアナログベースバンド信号に変換する可変周波数変換器と、
カットオフ周波数を変更でき、前記可変周波数変換器から出力される前記アナログベースバンド信号から高周波を除去する可変ローパスフィルタと、
前記可変ローパスフィルタから出力されるアナログベースバンド信号をディジタル信号に変換するアナログ-ディジタル変換器、とを少なくとも備え、
前記電力増幅器から出力される複数の搬送波の周波数帯域の無線周波数信号のうち、指定した搬送波の周波数帯域の無線周波数信号のみをベースバンド信号に変換して前記歪特性演算部へと出力し、指定した搬送波の周波数帯域を切り替えて異なる搬送波の周波数帯域の無線周波数信号をそれぞれベースバンド信号に変換することによって、複数の搬送波の周波数帯域のベースバンド信号を前記歪特性演算部へ出力する
付記2に記載した無線送信装置。
各搬送波の周波数帯域の無線周波数信号のみをそれぞれ通過させる複数のバンドパスフィルタと、
各搬送波の周波数帯域の無線周波数信号をそれぞれアナログベースバンド信号に変換する複数の周波数変換器と、
各搬送波の周波数帯域の前記周波数変換器から出力されたアナログベースバンド信号から高周波を除去する複数のローパスフィルタと、
各搬送波の周波数帯域の前記ローパスフィルタから出力されたアナログベースバンド信号をディジタル信号に変換するアナログ-ディジタル変換器、とを少なくとも備え、
前記電力増幅器から出力される複数の搬送波の周波数帯域の無線周波数信号をそれぞれ各搬送波の周波数帯域のベースバンド信号に変換して前記歪特性演算部へ出力する
付記2に記載した無線送信装置。
前記ローパスフィルタの入力信号および出力信号をそれぞれディジタル信号に変換するアナログ-ディジタル変換器と、
前記ローパスフィルタの前記入力信号と前記出力信号の相関関数を算出する相関関数計算機、を少なくとも備え、
前記相関関数計算機は、前記相関関数に基づいて前記ローパスフィルタにおける遅延時間を算出する
付記7に記載した無線送信装置。
前記遅延時間の差を補正された入力ベースバンド信号の高周波成分を除去し、
前記高周波成分を除去されたベースバンド信号を搬送波の周波数帯域の無線周波数信号に搬送させて出力し、
複数の前記搬送波の周波数帯域の各無線周波数信号を合成して出力する
付記8から10のいずれか一項に記載した無線送信方法。
前記複数の入力ベースバンド信号の高周波成分を除去し、
前記高周波成分を除去された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力し、
前記無線周波数信号の位相をそれぞれ補正し、
前記無線周波数信号の利得をそれぞれ補正し、
前記利得と前記位相が補正された前記無線周波数信号を合成して出力し、
前記複数の入力ベースバンド信号に前記歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、
前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号を出力するように、前記利得の補正量および前記位相の補正量を制御する
付記8または9に記載した無線送信方法。
前記複数の入力ベースバンド信号の高周波成分を除去し、
前記高周波成分を除去された前記複数の入力ベースバンド信号の位相をそれぞれ補正し、
前記高周波成分を除去された前記複数の入力ベースバンド信号の利得をそれぞれ補正し、
前記位相と前記利得が補正された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力し、
前記位相と前記利得が補正された前記複数の入力ベースバンド信号を搬送する複数の無線周波数信号を合成して出力し、
前記位相と前記利得が補正された前記複数の入力ベースバンド信号に前記歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、
前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号を出力するように、前記利得の補正量および前記位相の補正量を制御する
付記8または9に記載した無線送信方法。
1001、1001A プリディストーション部
1002、1002D、1002E マルチバンドRF信号発生器
1002A マルチバンド送信ブロック
1002B マルチバンド送信機ベースバンド部
1002C マルチバンド送信機RF部
1003 電力増幅器
1004 復調器
1011、1012、1013、1014、1015、1021、1503、1511、1702、1703、1704 端子
1101、1101A 送信機遅延補正部
1101kj、1103j 可変遅延手段
1102、1102A 歪補償制御信号生成部
1103 全体経路遅延補正部
1104 歪特性演算部
1201 ディジタル-アナログ変換器
1202 ローパスフィルタ
1203 周波数変換器
1204 RF信号合成器
1211 ミキサ
1212 局部発振(LO)信号発生器
1221 送信ブロック
1221B 送信ブロックベースバンド部
1301 可変バンドパスフィルタ
1302 可変周波数変換器
1303 可変ローパスフィルタ
1304、1802、1803 アナログ-ディジタル変換器
1311 ミキサ
1312 周波数可変LO信号発生器
1321 復調ブロック
1501 RF信号位相補正器
1501B ベースバンド信号位相補正器
1502 RF信号利得補正器
1502B ベースバンド信号利得補正器
1601 アナログ乗算器
1602 可変利得アンプ列
1603 ベースバンド信号加算器
1701 遅延検出器
1801 相関関数計算機
100、200 関連する無線送信装置
110A、110B 入力ベースバンド信号
115A、115B ベースバンド信号
120 プリディストーション部
125A、125B プリディストータ
130 デュアル・バンド送信機
135A、135B ローパスフィルタ
140A、140B 局部発振(LO)信号発生器
145A、145B ミキサ
150 電力合成器
160 電力増幅器
170 RF信号
Claims (10)
- 複数の入力ベースバンド信号をそれぞれ異なる周波数の搬送波に搬送させ、無線周波数信号として出力するマルチバンドRF信号発生手段と、
前記無線周波数信号を増幅して出力する電力増幅手段と、
前記複数の入力ベースバンド信号に、前記電力増幅手段の歪特性を補償する歪補償関数をそれぞれ施す歪補償制御信号生成手段と、
前記マルチバンドRF信号発生手段において前記複数の入力ベースバンド信号がそれぞれ受ける遅延時間の差を補正する送信機遅延補正手段、とを有する
無線送信装置。 - 請求項1に記載した無線送信装置において、
復調手段と、全体経路遅延補正手段と、歪特性演算手段とをさらに有し、
前記復調手段は、前記電力増幅手段から出力される前記無線周波数信号を搬送波の周波数帯域ごとに出力ベースバンド信号に変換し、
前記全体経路遅延補正手段は、前記歪補償制御信号生成手段の出力から前記復調手段の出力までの経路における前記搬送波の周波数帯域ごとの全体経路遅延時間に対応して、前記複数の入力ベースバンド信号ごとに遅延時間の補正を加え、
前記歪特性演算手段は、前記全体経路遅延補正手段から出力される遅延時間の補正を受けた前記複数の入力ベースバンド信号と、前記復調手段から出力される複数の前記出力ベースバンド信号とに基づいて、前記歪補償関数を前記搬送波の周波数帯域ごとに算出し、前記歪補償関数を前記歪補償制御信号生成手段に受け渡し、
さらに前記歪特性演算手段は、前記入力ベースバンド信号と前記出力ベースバンド信号の相関関数を算出し、前記相関関数に基づいて前記全体経路遅延時間を算出し、算出した前記全体経路遅延時間に基づいて前記全体経路遅延補正手段で加える遅延時間の補正量を決定する
無線送信装置。 - 請求項1または2に記載した無線送信装置において、
前記送信機遅延補正手段は、一の前記搬送波によって搬送される入力ベースバンド信号を、前記異なる周波数の個数分に分岐し、前記分岐した入力ベースバンド信号にそれぞれ遅延時間を付与し、
前記遅延時間はそれぞれ、前記一の搬送波によって搬送される入力ベースバンド信号が前記マルチバンドRF信号発生手段において受ける遅延と、他の搬送波によって搬送される入力ベースバンド信号が前記マルチバンドRF信号発生手段において受ける遅延との差である
無線送信装置。 - 請求項1から3のいずれか一項に記載した無線送信装置において、
前記マルチバンドRF信号発生手段は、複数のローパスフィルタと、複数の周波数変換手段と、RF信号合成手段、とを少なくとも備え、
前記ローパスフィルタは、前記歪補償制御信号生成手段から入力されたベースバンド信号の高周波成分を除去し、
前記周波数変換手段は、前記ローパスフィルタから出力された前記ベースバンド信号を搬送波の周波数帯域の無線周波数信号に搬送させて出力し、
前記RF信号合成手段は、複数の前記周波数変換手段から出力された前記搬送波の周波数帯域の各無線周波数信号を合成して出力する
無線送信装置。 - 請求項1または2に記載した無線送信装置において、
前記マルチバンドRF信号発生手段は、
前記複数の入力ベースバンド信号の高周波成分を除去する複数のローパスフィルタと、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力する複数の周波数変換手段と、
前記周波数変換手段から出力された前記無線周波数信号の位相をそれぞれ補正する複数のRF信号位相補正手段と、
前記周波数変換手段から出力された前記無線周波数信号の利得をそれぞれ補正する複数のRF信号利得補正手段と、
前記RF信号利得補正手段および前記RF信号位相補正手段において利得と位相が補正された前記無線周波数信号を合成して出力するRF信号合成手段、とを少なくとも備え、
前記歪補償制御信号生成手段は、前記複数の入力ベースバンド信号に前記電力増幅手段の歪特性を補償する歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号が前記マルチバンドRF信号発生手段から出力するように、前記RF信号利得補正手段における利得補正量および前記RF信号位相補正手段における位相補正量を制御する
無線送信装置。 - 請求項1または2に記載した無線送信装置において、
前記マルチバンドRF信号発生手段は、
前記複数の入力ベースバンド信号の高周波成分を除去する複数のローパスフィルタと、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号の位相をそれぞれ補正する複数のベースバンド信号位相補正手段と、
前記ローパスフィルタから出力された前記複数の入力ベースバンド信号の利得をそれぞれ補正する複数のベースバンド信号利得補正手段と、
前記ベースバンド信号位相補正手段および前記ベースバンド信号利得補正手段から出力された前記複数の入力ベースバンド信号を搬送波の周波数帯域の無線周波数信号にそれぞれ搬送させて出力する複数の周波数変換手段と、
前記周波数変換手段からそれぞれ出力された前記無線周波数信号を合成して出力するRF信号合成手段、とを少なくとも備え、
前記歪補償制御信号生成手段は、前記複数の入力ベースバンド信号に前記電力増幅手段の歪特性を補償する歪補償関数をそれぞれ施した補正ベースバンド信号を生成し、前記補正ベースバンド信号を搬送する搬送波の周波数帯域の無線周波数信号が前記マルチバンドRF信号発生手段から出力するように、前記ベースバンド信号利得補正手段における利得補正量および前記ベースバンド信号位相補正手段における位相補正量を制御する
無線送信装置。 - 請求項4から6のいずれか一項に記載した無線送信装置において、
前記マルチバンドRF信号発生手段は、前記ローパスフィルタの遅延時間を検出する遅延検出手段をさらに有し、
前記遅延検出手段は、検出した前記ローパスフィルタの遅延時間を前記送信機遅延補正手段に送出し、
前記送信機遅延補正手段は、前記ローパスフィルタの遅延時間を、前記マルチバンドRF信号発生手段において前記複数の入力ベースバンド信号がそれぞれ受ける遅延の差として補正する
無線送信装置。 - 複数の入力ベースバンド信号をそれぞれ異なる周波数の搬送波に搬送させた無線周波数信号を生成する際に、前記複数の入力ベースバンド信号がそれぞれ受ける遅延時間の差を補正し、
前記遅延時間の差を補正された前記複数の入力ベースバンド信号に、前記無線周波数信号を増幅する際における歪特性を補償する歪補償関数をそれぞれ施す
無線送信方法。 - 請求項8に記載した無線送信方法において、
増幅された前記無線周波数信号を搬送波の周波数帯域ごとに出力ベースバンド信号に変換し、
前記入力ベースバンド信号と前記出力ベースバンド信号の相関関数を算出し、
前記相関関数に基づいて、前記入力ベースバンド信号が前記歪補償関数を施されてから前記出力ベースバンド信号に変換されるまでに受ける遅延時間である全体経路遅延時間を算出し、
前記全体経路遅延時間に基づいて、前記入力ベースバンド信号ごとに遅延時間の差を補正し、
前記遅延時間の差の補正を受けた前記入力ベースバンド信号と、前記出力ベースバンド信号とに基づいて、前記歪補償関数を前記搬送波の周波数帯域ごとに算出する
無線送信方法。 - 請求項8または9に記載した無線送信方法において、
前記遅延時間の差を補正する際に、
一の前記搬送波によって搬送される入力ベースバンド信号を、前記異なる周波数の個数分に分岐し、前記分岐した入力ベースバンド信号にそれぞれ遅延時間を付与し、
前記遅延時間はそれぞれ、前記増幅する際に前記一の搬送波によって搬送される入力ベースバンド信号が受ける遅延と、前記増幅する際に他の搬送波によって搬送される入力ベースバンド信号が受ける遅延との差である
無線送信方法。
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CN112291175A (zh) * | 2020-10-29 | 2021-01-29 | 上海擎昆信息科技有限公司 | 一种基于定时控制的基带上行发送装置 |
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JPWO2014136437A1 (ja) | 2017-02-09 |
US20160013820A1 (en) | 2016-01-14 |
JP6265206B2 (ja) | 2018-01-24 |
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