JP2007049621A - Pre-distortion amplifying device - Google Patents

Pre-distortion amplifying device Download PDF

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Publication number
JP2007049621A
JP2007049621A JP2005234559A JP2005234559A JP2007049621A JP 2007049621 A JP2007049621 A JP 2007049621A JP 2005234559 A JP2005234559 A JP 2005234559A JP 2005234559 A JP2005234559 A JP 2005234559A JP 2007049621 A JP2007049621 A JP 2007049621A
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temperature
baseband signal
power amplifier
transmission
transmission baseband
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JP2005234559A
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Japanese (ja)
Inventor
Masaru Adachi
Yasushi Nakayama
Kenya Tomaru
裕史 中山
勝 安達
賢也 戸丸
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Hitachi Kokusai Electric Inc
株式会社日立国際電気
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a pre-distortion amplifying device whose circuitry can be simplified and downsized and which can compensate distortions depending on a temperature variation of a power amplifier. <P>SOLUTION: The pre-distortion amplifying device 100 is equipped with a symbol mapping unit 102, which compares temperature data input from a temperature detector 110 with a given threshold value to select a symbol map depending on a temperature characteristic. Then, a serial transmission bit train that has been input is brought into a check with the symbol map selected to output a mapping value. At this time, a symbol map is used to which added is an inverse characteristic of nonlinear distortions generated by the power amplifier 108. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a predistortion amplification apparatus that compensates for nonlinear distortion generated by a power amplifier of a transmission apparatus in a wireless communication system.

  Conventionally, a power amplifier used in a transmission apparatus of a wireless communication system has to be operated at the highest possible operating point from the viewpoint of power efficiency. However, in general, when the power efficiency of a power amplifier is increased, the influence of input / output characteristics due to nonlinear distortion increases, and therefore, a nonlinear distortion compensation technique is used. Various methods have been proposed as a distortion compensation technique. In particular, the predistortion method can obtain highly accurate and stable distortion compensation characteristics by using digital signal processing in the baseband (for example, patents). See reference 1.)

JP 2003-258563 A

  By the way, the conventional predistortion amplifying device requires a memory for storing the distortion compensation coefficient. Further, calculation processing such as power value calculation and complex multiplication of the distortion compensation coefficient and the transmission baseband signal is required, so that the circuit configuration is complicated and large. In general, the predistortion method is used to reduce the leakage power of the adjacent channel of the power amplifier. Even if the leakage power has a size that does not affect the adjacent channel, it is generated in the power amplifier. Due to the distortion, the constellation of the symbol point may be distorted and the bit error rate may be degraded. In order to correct such distortion, the conventional predistortion amplification device requires a large circuit such as a feedback system.

  In general, it is known that the input / output characteristics of a power amplifier change according to the temperature around the power amplifier. In order to cope with the change in the strain amount due to the temperature change, it is necessary to store a distortion compensation coefficient corresponding to the temperature change, which requires more memory capacity.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to make it possible to simplify and downsize the circuit configuration and to perform distortion compensation according to the temperature change of the power amplifier. The object is to provide a distortion amplifying apparatus.

In order to solve the above-mentioned object, a predistortion amplification device according to the present invention includes a transmission baseband signal generator that maps a transmission bit string on a complex plane and outputs a transmission baseband signal representing the mapping value, and the transmission A radio signal generation unit that generates a radio signal modulated by a transmission baseband signal output from the baseband signal generation unit; a power amplifier that amplifies and outputs the radio signal generated by the radio signal generation unit; A temperature detector for detecting a temperature around the power amplifier. The transmission baseband signal generation unit stores a plurality of sets of mapping values that reflect the distortion characteristics of the power amplifier and a temperature determination unit that compares the temperature with a threshold value, in association with the temperature, and is input Mapping means for outputting a mapping value corresponding to the transmission bit string and the determination result by the temperature determination unit, and transmission filter means for generating a transmission baseband signal representing the mapping value are provided.

  In the above configuration, a plurality of mapping values reflecting the inverse characteristics of the nonlinear distortion generated in the power amplifier are stored in correspondence with the temperature of the power amplifier, and the mapping value corresponding to the detected temperature is used. It is possible to compensate for non-linear distortion corresponding to temperature. As a result, the circuit configuration can be simplified and reduced in size, and distortion compensation according to the temperature change of the power amplifier can be realized.

The present invention is also characterized by having the following various configurations.
A first configuration includes a transmission baseband signal generation unit that maps a transmission bit string on a complex plane and outputs a transmission baseband signal representing the mapping value, and a transmission baseband output from the transmission baseband signal generation unit A radio signal generator that generates a radio signal modulated by the signal, a power amplifier that amplifies and outputs the radio signal generated by the radio signal generator, and a temperature detector that detects the temperature around the power amplifier It comprises. The transmission baseband signal generation unit multiplies a temperature determination unit that compares the temperature with a threshold value, a mapping value that reflects an inverse characteristic of the distortion characteristic of the power amplifier, and a tap coefficient that defines a transmission filter characteristic. A plurality of sets of values are stored in association with the temperature, a memory for outputting a multiplication value corresponding to the input transmission bit string and a determination result by the temperature determination unit, and a time series of the multiplication value output from the memory And an adder for outputting the transmission baseband signal.

  Even with this configuration, the circuit configuration can be simplified and downsized as in the case of the above-described invention, and distortion compensation according to the temperature change of the power amplifier can be realized. Furthermore, since the multiplication value of the mapping value and the tap coefficient that defines the transmission filter characteristic is stored in advance in the memory, a multiplier is not required, and thus the circuit configuration can be further simplified and reduced in size.

  In the second configuration, a transmission bit string is mapped on a complex plane according to a modulation scheme adaptively selected from a plurality of types of modulation schemes, and a transmission baseband signal representing the mapping value is output. A transmission baseband signal generation unit, a radio signal generation unit that generates a radio signal modulated by the transmission baseband signal output from the transmission baseband signal generation unit, and a radio signal generated by the radio signal generation unit A power amplifier that amplifies and outputs power; and a temperature detector that detects a temperature around the power amplifier. The transmission baseband signal generation unit multiplies a temperature determination unit that compares the temperature with a threshold value, a mapping value that reflects an inverse characteristic of the distortion characteristic of the power amplifier, and a tap coefficient that defines a transmission filter characteristic. A plurality of values are stored in association with each of the temperature and the plurality of types of modulation schemes, and a multiplication value corresponding to the input transmission bit string and the determination result by the temperature determination unit and the selected modulation scheme is stored. A memory for outputting, and an adder for adding the multiplication values output from the memory in time series and outputting the transmission baseband signal.

  With this configuration, a mapping value that reflects the inverse characteristic of the distortion characteristic that takes into account the temperature change of the power amplifier is used in accordance with the modulation method adaptively selected from among a plurality of types of modulation methods. As a result, it is possible to reliably compensate for the distortion characteristics generated according to the temperature change of the power amplifier and a plurality of types of modulation schemes.

  In short, according to the present invention, it is possible to provide a predistortion amplifying device that enables simplification and miniaturization of the circuit configuration and enables distortion compensation in accordance with a temperature change of the power amplifier.

(First embodiment)
FIG. 1 is a circuit block diagram showing a configuration of a transmission apparatus including a predistortion amplification apparatus according to the first embodiment of the present invention. In this embodiment, a case where the modulation scheme is 16QAM (16-positions Quadrature Amplitude Modulation) and the nonlinear distortion generated in the power amplifier is a distortion due to a phase will be described as an example.
This transmission device includes a predistortion amplification device 100 and an antenna 109. The predistortion amplification apparatus 100 includes a symbol mapping unit (with distortion compensation) 102, and further includes a transmission filter unit 103, a quadrature modulation unit 104, a DA converter 105, a mixer 106, an oscillator 107, and a power amplifier 108. And a temperature detector 110.

The symbol mapping unit (with distortion compensation) 102 associates the input serial transmission bit string with a symbol map reflecting the inverse characteristic of distortion, and outputs the mapping value.
The transmission filter unit 103 includes a multiplication unit 1031 and an addition unit 1032. FIG. 2 shows a circuit configuration of the transmission filter unit 103. The transmission filter unit 103 multiplies the mapping value input from the symbol mapping unit 102 by the multiplication unit 1031 and a tap coefficient that defines transmission filter characteristics, and then sequentially adds the multiplication results by the addition unit 1032. Thus, a filtering process is performed to generate and output a baseband signal.

  The quadrature modulation unit 104 performs quadrature modulation on the baseband signal input from the transmission filter unit 103 and converts the baseband signal into a radio frequency signal. The DA converter 105 analog-converts the converted radio frequency signal and outputs an analog signal. In the mixer 106, the analog signal output from the DA converter 105 is mixed with the oscillation signal from the oscillator 107 and up-converted. The up-converted signal is amplified by the power amplifier 108 and then transmitted to the radio line via the antenna 109. The temperature detector 110 measures the temperature around the power amplifier 108 and supplies temperature data to the symbol mapping unit 102.

  FIG. 3 is a block configuration diagram showing a specific configuration of the symbol mapping unit 102. The symbol mapping unit 102 includes a plurality of symbol maps (symbol maps a and b in the figure as examples) corresponding to changes in strain characteristics due to temperature. Further, a temperature determination unit 1022 that compares the temperature data supplied from the temperature detector 110 with a predetermined threshold value, and a switch 1021 that performs selection switching of the plurality of symbol maps based on the determination result of the temperature determination unit 1022. Prepare. With such a configuration, the symbol mapping unit 102 performs mapping processing using a symbol map corresponding to a change in strain characteristics due to temperature based on the temperature data detected by the temperature detector 110.

  Here, a symbol map used in the symbol mapping unit 102 will be described. If a symbol map without distortion compensation as shown in FIG. 4 is used, distortion characteristics due to the power amplifier 108 as shown in FIG. 5 occur in the output signal from the power amplifier 108. Therefore, in the present invention, in order to reduce this distortion characteristic, a symbol map reflecting the inverse characteristic of distortion generated by the power amplifier 108 is used. FIG. 6 shows an example of a 16QAM symbol map used in the symbol mapping unit 102.

That is, assuming that the distortion of the power amplifier 108 is dominated by the third-order phase distortion, the symbol map uses a third-order compensation curve as shown in FIG. It becomes a symbol map. An example of the third-order compensation curve used here is shown in equation (1).
y = −0.6 × 10 −4 x 3 [deg] (1)
As shown in FIG. 8, it can be seen that the phase distortion of each mapping value increases as the distance from the origin increases, that is, the amplitude of the input signal increases. It can be seen that the phase distortion generated in the power amplifier 108 is compensated as compared with the conventional constellation that does not perform distortion compensation indicated by the crosses.

  Further, since the input / output characteristics of the power amplifier 108 change due to a change in ambient temperature, the amount of distortion also varies. Therefore, it is necessary to correct distortion due to temperature change. Even when distortion fluctuation due to temperature change is compensated, distortion compensation is performed only by changing the mapping point of the symbol map described above according to the temperature characteristics.

Next, the operation of the predistortion amplifier 100 will be described in detail. FIG. 9 is a diagram illustrating the operation of the symbol mapping unit 102.
Prior to FIG. 9, the symbol mapping unit 102 selects a symbol map corresponding to the temperature characteristics. That is, the temperature detector 110 measures the temperature around the power amplifier 108 and supplies temperature data to the symbol mapping unit 102. A temperature determination unit 1022 provided in the symbol mapping unit 102 compares the supplied temperature data with a predetermined threshold value and supplies a switch control signal to the switch 1021 for selecting a symbol map corresponding to the temperature characteristics. Send it out. Based on this switch control signal, the switch 1021 selects and switches the symbol map a or b.

In FIG. 9, a symbol mapping unit (with distortion compensation) 102 associates an input serial transmission bit string on the selected symbol map and outputs amplitude information thereof. For example, as shown in FIG. 9, when the input serial transmission bit string is “01001011”, I 0 Q 0 (−2.6, −6.8), I 1 Q 1 (7. 1, 1.9) are mapped in order, and the symbol mapping unit 102 performs "-2.6" and "7.1" as I-side data, "-6.8" as Q-side data, The mapping values are output in the order of “1.9”.

  Then, transmission filter section 103 performs band limitation and waveform shaping using the above mapping value for each IQ input from symbol mapping section 102, and outputs a baseband signal. The baseband signal output from the transmission filter unit 103 is quadrature modulated by the quadrature modulation unit 104 and then converted to an analog signal by the DA converter 105. In the mixer 106, the analog signal output from the DA converter 105 is mixed with the oscillation signal from the oscillator 107 and up-converted to a radio frequency. Then, the power amplifier 108 amplifies the upconverted signal to a desired level. During this amplification processing, nonlinear phase distortion occurs in the power amplifier 108. In this configuration, since the phase distortion is compensated at the time of mapping processing in the symbol mapping unit 102, the output of the power amplifier 108 is nonlinear. The output value is compensated for the phase distortion. Thus, the modulated signal amplified by the power amplifier 108 is output from the antenna 109.

  As described above, in the first embodiment of the present invention, the predistortion amplifying apparatus 100 includes the symbol mapping unit 102, which uses the temperature data input from the temperature detector 110. Compared with a predetermined threshold value, a symbol map corresponding to the temperature characteristic is selected. The input serial transmission bit string is collated with the selected symbol map, and a mapping value is output. At this time, a symbol map to which a reverse characteristic of the distortion characteristic generated by the power amplifier 108 is added is used.

  Therefore, according to the first embodiment, when the nonlinear distortion of the power amplifier 108 is a distortion due to the phase, the phase distortion of the power amplifier 108 is obtained by adding the inverse characteristic of the phase distortion as shown in FIG. Distortion can be compensated. For this reason, memory processing for storing distortion compensation coefficients and computation processing such as power value calculation and complex multiplication of distortion compensation coefficients and transmission baseband signals are required, as in the prior art predistortion amplifier. Therefore, the circuit configuration is reduced in size and simplified, and the processing speed is improved. In particular, since the phase distortion compensation of the power amplifier can be realized only by changing only the symbol map, nonlinear distortion compensation can be easily realized.

  Further, since a plurality of mapping values for compensating the distortion characteristics corresponding to the temperature of the power amplifier are stored and the mapping values are used according to the detected temperature, it is possible to reliably compensate for the distortion amount in the power amplifier due to temperature change. it can. This can be realized by measuring the amount of strain at a predetermined temperature in advance and using a plurality of symbol maps using the temperature as a parameter. For example, as shown in FIG. 3, two symbol maps a and b corresponding to the temperature are provided, and which symbol map is used is switched based on the temperature around the power amplifier 108 from the temperature detector 110. .

  In the first embodiment, the phase distortion generated by the power amplifier 108 has been described as an example. However, when amplitude distortion or both amplitude distortion and phase distortion occur, the same applies to each case. It is possible to perform distortion compensation by changing the symbol map to reflect the distortion compensation characteristics.

(Second Embodiment)
FIG. 10 is a circuit block diagram showing a configuration of a transmission apparatus including a predistortion amplification apparatus according to the second embodiment of the present invention. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Also in this embodiment, as in the first embodiment, the case where the modulation scheme is 16QAM and the nonlinear distortion generated in the power amplifier is distortion due to phase will be described as an example.

  This transmission device includes a predistortion amplification device 200 and an antenna 109. The predistortion amplification apparatus 200 includes an addressing unit 201 and a transmission filter unit 202, and further includes an orthogonal modulation unit 104, a DA converter 105, a mixer 106, an oscillator 107, a power amplifier 108, and a temperature detector. 110. The temperature detector 110 supplies temperature data obtained by the measurement to the addressing unit 201. The transmission filter unit 202 includes a memory unit 203 and an addition unit 204. FIG. 11 shows the configuration of the transmission filter unit 202.

  Here, the configuration of the transmission filter unit 202 will be described in comparison with the transmission filter unit 103 of the first embodiment. The data input to the transmission filter unit 103 illustrated in FIG. 2 is a symbol map value output from the symbol mapping unit 102 as described above. That is, the multiplication unit 1031 has a symbol map value that is a fixed value (16 types if the distortion-compensated 16QAM symbol map shown in FIG. 6 is used) and a known tap coefficient that is a fixed value. Perform multiplication. Therefore, as shown in FIG. 11, the multiplication result can be stored in the memories 203a, 203b, 203c in advance, and the multiplier 1031 can be replaced with the memories 203a, 203b, 203c to constitute the transmission filter unit 202.

  The memories 203a, 203b, and 203c each store a plurality of sets of multiplication values of symbol mapping values reflecting the inverse characteristics of the distortion characteristics of the power amplifier 108 and tap coefficients that define the transmission filter characteristics in association with the temperatures. is doing. The addressing unit 201 compares and determines a predetermined threshold value based on the temperature data supplied from the temperature detector 110, and outputs an address value that stores a multiplication value corresponding to the temperature to the transmission filter 202.

  In this case, the input data to the transmission filter unit 202 is an address value of the memories 203a, 203b, 203c corresponding to the mapping value. This address value is output by the addressing unit 201, and the addressing unit 201 converts the input serial transmission bit string into an address value corresponding to the memory unit 203. FIG. 12 shows the data structure of the memory unit 203. The memory unit 203 includes memories 203a, 203b, and 203c, and each of the memories 203a, 203b, and 203c stores a multiplication result of 16 kinds of symbol map values and tap coefficients. That is, the multiplication result stored in each of the memories 203a, 203b, and 203c is a multiplication result of the symbol map value and the tap coefficient as shown in FIG. 6 in which the phase distortion of the power amplifier 108 is compensated. The adding unit 204 performs a filtering process by sequentially delaying and adding the multiplication results output from the memory unit 203, and outputs a baseband signal.

Next, the operation of the predistortion amplifier 200 will be described with reference to FIG. FIG. 13 is a diagram illustrating the operation of the addressing unit 201.
First, the addressing unit 201 outputs an address value for the memory unit 203 corresponding to the symbol value based on the input serial transmission bit string and the temperature data supplied from the temperature detector 110. For example, when the serial transmission bit string inputted as shown in FIG. 13 is “01001011” and the data arrangement of the memory unit 203 is the arrangement shown in FIG. 12, I 0 Q 0 (−2.6 in the IQ coordinates). , −6.8) and I 1 Q 1 (7.1, 1.9) are mapped in this order, and “0100” and “1011” are output as address values for the memory unit 203. To do.

  The memory unit 203 stores in advance a plurality of sets of the result of multiplying the symbol map value of FIG. 6 to which the phase distortion is added and the tap coefficient in association with the temperature as described above, and the transmission filter unit 202 stores the result from the memory unit 203. The output value is sequentially added by the adding unit 204 to perform band limitation and waveform shaping, and output a baseband signal. The baseband signal output from the transmission filter unit 202 is quadrature modulated by the quadrature modulation unit 104 and then converted to an analog signal by the DA converter 105. In the mixer 106, the analog signal output from the DA converter 105 is mixed with the oscillation signal from the oscillator 107 and up-converted to a radio frequency. Then, the power amplifier 108 amplifies the upconverted signal to a desired level. During this amplification processing, nonlinear phase distortion occurs in the power amplifier 108. In this configuration, since a symbol map compensated for phase distortion is used, the output of the power amplifier 108 is an output value compensated for nonlinear phase distortion. Become. Thus, the modulated signal amplified by the power amplifier 108 is output from the antenna 109.

  As described above, in the second embodiment, a symbol map in which nonlinear distortion generated by the power amplifier 108 is compensated in advance is used in association with temperature, and further, a finite symbol map value that is nonlinear distortion compensated and a fixed tap are used. The transmission filter unit 202 is configured using the memory unit 203 that stores the coefficient multiplication results. As a result, the multiplier 1031 is not required, and the circuit can be downsized, the processing speed can be increased, the circuit configuration can be simplified, and distortion compensation according to the temperature change of the power amplifier can be realized.

(Third embodiment)
FIG. 14 is a circuit block diagram showing a configuration of a transmission apparatus including a predistortion amplification apparatus according to the third embodiment of the present invention. In the figure, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The predistortion amplifying apparatus 300 according to the third embodiment corresponds to adaptive modulation that switches a plurality of modulation schemes. Here, as an example, in addition to 16QAM, BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), and 64QAM (64-positions Quadrature Amplitude Modulation) are supported.

  The predistortion amplification apparatus 300 includes an addressing unit 301 and a transmission filter unit 302, and further includes a quadrature modulation unit 104, a DA converter 105, a mixer 106, an oscillator 107, a power amplifier 108, and a temperature detector. 110. The transmission filter unit 302 includes a memory unit 303 and an addition unit 304. FIG. 15 shows the configuration of the memory unit 303. The memory unit 303 stores data for each modulation method in association with the temperature, as shown in FIG. 15, and the memories 303a, 303b, and 303c constituting the memory unit 303 store nonlinear data corresponding to each modulation method. The multiplication result of the distortion-compensated symbol map value and the tap coefficient is stored. As shown in FIG. 15, the classification of each modulation method is represented by using, for example, the upper 2 bits of the address value.

  On the other hand, the addressing unit 301 receives a modulation method together with the serial transmission bit string and the temperature data supplied from the temperature detector 110, and the address of the memory unit 303 corresponding to the input serial transmission bit string, the temperature data, and the modulation method. A value is output from the addressing unit 301. The transmission filter unit 302 performs band limitation and waveform shaping by sequentially adding the multiplication result of the symbol map value corresponding to the output address value and the tap coefficient by the adding unit 204, and outputs a baseband signal. After that, the same processing as in the second embodiment is performed based on the baseband signal output from the transmission filter unit 302, and a radio signal is transmitted.

  In the third embodiment of the present invention, the multiplication result of the symbol map value compensated for nonlinear distortion and the tap coefficient corresponding to a plurality of modulation schemes is stored in the memory unit 303 in association with the temperature of the power amplifier 108. deep. Further, the addressing unit 301 accepts the input of the modulation method together with the serial transmission bit string and the temperature data obtained by the temperature detector 110, and based on the input serial transmission bit string and the temperature data and the modulation method, the temperature characteristics and Distortion compensation corresponding to the modulation method is performed. As a result, in a transmission apparatus having an adaptive modulation function, since a memory to which a symbol map corresponding to the temperature and the modulation method is applied is referred to, not only the modulation method but also high-accuracy distortion compensation considering the temperature characteristics is performed. It can be carried out.

The present invention is not limited to the above-described embodiments. For example, the circuit configuration of the predistortion amplifier and the modulation scheme to be supported are variously modified and implemented without departing from the gist of the present invention. it can.
In short, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in each embodiment. Furthermore, you may combine the component covering different embodiment suitably.

1 is a circuit block diagram showing a configuration of a transmission apparatus including a predistortion amplification apparatus according to a first embodiment of the present invention. The figure which shows the structure of the transmission filter part shown in FIG. The figure which shows the structure of the symbol mapping part shown in FIG. The figure which shows an example of the conventional 16QAM constellation. The figure which shows an example of the constellation of 16QAM to which the phase distortion was added. The figure which shows an example of the constellation of 16QAM which compensated the phase distortion. The figure which shows an example of the characteristic of a phase distortion. The figure which shows an example of the symbol map (with / without distortion compensation) of 16QAM. The figure which shows operation | movement of the symbol mapping part shown in FIG. The circuit block diagram which shows the structure of the transmitter provided with the predistortion amplifier concerning 2nd Embodiment of this invention. The figure which shows the structure of the transmission filter part shown in FIG. The figure which shows the data structure memorize | stored in the memory part shown in FIG. The figure which shows operation | movement of the addressing part shown in FIG. The circuit block diagram which shows the structure of the transmitter provided with the predistortion amplifier concerning 3rd Embodiment of this invention. The figure which shows the data structure memorize | stored in a memory part, when respond | corresponding to an adaptive modulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Predistortion amplifier, 102 ... Symbol mapping part, 103 ... Transmission filter part, 104 ... Quadrature modulation part, 105 ... DA converter, 106 ... Mixer, 107 ... Oscillator, 108 ... Power amplifier, 109 ... Antenna, 110 ... Temperature detector, 1021... Switch, 1022... Temperature determination unit, 200... Predistortion amplification device, 201... Addressing unit, 202 ... transmission filter unit, 203 ... memory unit, 204 ... addition unit, 300 ... predistortion amplification device, 301 ... Addressing section, 302 ... Transmission filter section, 303 ... Memory section, 1031 ... Multiplication section, 1032 ... Addition section, 203a, 203b, 203c ... Memory, 303a, 303b, 303c ... Memory.

Claims (3)

  1. A transmission baseband signal generation unit that maps a transmission bit string on a complex plane and outputs a transmission baseband signal representing the mapping value, and a radio modulated by the transmission baseband signal output from the transmission baseband signal generation unit A radio signal generation unit that generates a signal, a power amplifier that amplifies and outputs the radio signal generated by the radio signal generation unit, and a temperature detector that detects a temperature around the power amplifier,
    The transmission baseband signal generator is
    Determining means for comparing the temperature with a threshold;
    Mapping means for storing a plurality of sets of mapping values reflecting the distortion characteristics of the power amplifier in association with the temperature, and outputting mapping values corresponding to the input transmission bit string and the determination result by the temperature determination unit;
    A predistortion amplifying apparatus comprising: transmission filter means for generating a transmission baseband signal representing the mapping value.
  2. A transmission baseband signal generation unit that maps a transmission bit string on a complex plane and outputs a transmission baseband signal representing the mapping value, and a radio modulated by the transmission baseband signal output from the transmission baseband signal generation unit A radio signal generation unit that generates a signal, a power amplifier that amplifies and outputs the radio signal generated by the radio signal generation unit, and a temperature detector that detects a temperature around the power amplifier,
    The transmission baseband signal generator is
    A temperature determination unit that compares the temperature with a threshold;
    A plurality of sets of multiplication values of mapping values reflecting inverse characteristics of distortion characteristics of the power amplifier and tap coefficients defining transmission filter characteristics are stored in association with the temperatures, and the input transmission bit string and the temperature A memory that outputs a multiplication value corresponding to a determination result by the determination unit;
    A predistortion amplification apparatus comprising: an adder that adds the multiplication values output from the memory in a time series and outputs the transmission baseband signal.
  3. A transmission baseband signal generator that maps a transmission bit string on a complex plane according to a modulation scheme adaptively selected from a plurality of types of modulation schemes, and outputs a transmission baseband signal representing the mapping value; A radio signal generation unit that generates a radio signal modulated by a transmission baseband signal output from the transmission baseband signal generation unit, and a power amplifier that amplifies and outputs the radio signal generated by the radio signal generation unit And a temperature detector for detecting the temperature around the power amplifier,
    The transmission baseband signal generator is
    A temperature determination unit that compares the temperature with a threshold;
    A plurality of sets of mapping values that reflect the inverse characteristics of the distortion characteristics of the power amplifier and tap coefficients that define transmission filter characteristics are associated with each of the temperature and the plurality of modulation schemes; A memory that outputs a multiplication value corresponding to the input transmission bit string and the determination result by the temperature determination unit and the selected modulation method;
    A predistortion amplification apparatus comprising: an adder that adds the multiplication values output from the memory in a time series and outputs the transmission baseband signal.
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EP2515444A1 (en) * 2011-04-21 2012-10-24 MediaTek Singapore Pte Ltd. RF transmitter and method therefor
US9088319B2 (en) 2011-04-21 2015-07-21 Mediatek Singapore Pte. Ltd. RF transmitter architecture, integrated circuit device, wireless communication unit and method therefor
JP2016086368A (en) * 2014-10-28 2016-05-19 富士通株式会社 Transmission device and transmission method
US9559879B2 (en) 2011-04-21 2017-01-31 Mediatek Singapore Pte. Ltd. PA cell, PA module, wireless communication unit, RF transmitter architecture and method therefor
US10129055B2 (en) 2011-04-21 2018-11-13 Mediatek Singapore Pte. Ltd. PA cell, PA module, wireless communication unit, RF transmitter architecture and method therefor

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