JP2016134874A - Communication device, communication system, and distortion compensation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device which can satisfactorily restrain an influence by the nonlinear distortion of a signal produced during propagation etc.SOLUTION: Storage means 16 stores a coefficient to be applied to a distortion compensation circuit 14 which executes distortion compensation processing on a signal. Control means 17 requests a transmission side to control transmission power according to reception signal intensity, to indicate to the distortion compensation circuit 14 a coefficient to be applied by reading from the storage means 16 according to the transmission power on the transmission side. The distortion compensation circuit 14 reads out from the storage means 16 a coefficient according to the instruction of the control means 17, to execute distortion compensation processing on the signal based on a reception signal, using the readout coefficient.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a communication device, a communication system, and a distortion compensation method for receiving a signal.

  In order to transmit and receive data at high speed in a wireless communication system, it is required to adopt a digital modulation scheme such as QAM (Quadrature Amplitude Modulation) and to increase the number of values. In a digital modulation system with more multivalue, a higher signal-to-noise ratio (Signal-Noise ratio) is required. In order to further increase the S / N ratio, it is necessary to reduce the amount of fixed deterioration caused by nonlinear distortion.

  In a wireless communication system, a nonlinear distortion compensation circuit is preferably used in order to suppress nonlinear distortion of a signal without reducing the dynamic range of transmission power or reducing power efficiency.

  Further, in a wireless communication system that performs communication using microwave band radio waves, when a received signal level (RSL: Received Signal Level) changes due to fading, it is necessary to change the transmission power following the change. Such a technique for changing the transmission power is called ATPC (Automatic Transmit Power Control). In ATPC, the transmission power changes by, for example, 100 dB per second.

  Then, the distortion compensation circuit must also operate with high accuracy and high speed.

  Patent Literature 1 describes a transmitter that performs distortion compensation processing on a signal using a coefficient read from a preset table.

International Publication No. 2013/179399

  However, in general, the accuracy and speed of the distortion compensation processing in the distortion compensation circuit are in a trade-off relationship, and it is difficult to sufficiently improve both performances.

  Further, since the transmitter described in Patent Document 1 performs distortion compensation processing before a signal is transmitted, it cannot cope with fading or the like that occurs during propagation of the signal.

  Accordingly, an object of the present invention is to provide a communication device, a communication system, and a distortion compensation method that can satisfactorily suppress the influence of nonlinear distortion of a signal generated during propagation or the like.

  A communication apparatus according to the present invention requests storage means for storing a coefficient to be applied to a distortion compensation circuit that performs distortion compensation processing on a signal, and controls transmission power on the transmission side according to the strength of the received signal. Control means for instructing the distortion compensation circuit to read out and apply the coefficient from the storage means according to the transmission power, and read out the coefficient according to the instruction from the control means from the storage means, And a distortion compensation circuit for performing distortion compensation processing.

  The communication system according to the present invention includes a plurality of communication devices according to any of the aspects, and each of the control units of the plurality of communication devices indicates a coefficient when the coefficient to be read and applied from the storage unit is instructed to the distortion compensation circuit. Information is notified to another communication apparatus, and when the information indicating the coefficient is notified from another communication apparatus, the distortion compensation circuit of the communication apparatus is instructed to read and apply the coefficient from the storage unit. And

  According to the distortion compensation method of the present invention, a distortion compensation circuit that requests transmission power control on the transmission side according to the intensity of a received signal, reads out from the storage means, and performs distortion compensation processing on the signal according to the transmission power on the transmission side. A control step for instructing a distortion compensation circuit on a coefficient to be applied to the distortion, a coefficient corresponding to the instruction in the control step is read from the storage means, and the distortion compensation circuit is subjected to distortion compensation processing on the signal using the read coefficient And a compensation step.

  According to the present invention, it is possible to satisfactorily suppress the influence of nonlinear distortion of a signal generated during propagation or the like.

It is a block diagram which shows the structural example of the communication apparatus of the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the reception distortion compensation circuit and control circuit in the communication apparatus of the 1st Embodiment of this invention. It is explanatory drawing which shows the example of the coefficient memorize | stored in memory. It is explanatory drawing which shows the example of the change of the transmission power value Pout_Tx which signal strength information shows, and the change of the index according to the coefficient read from memory according to transmission power value Pout_Tx. It is a block diagram which shows the structural example for adjusting the coefficient read and applied from the memory by the process of step S108. It is explanatory drawing which shows the change of the absolute value of the value of the addition result by an adder. It is explanatory drawing which shows the example of the 1st table for setting a coefficient according to transmission power Pout_Tx and the intensity | strength T_RSL of the preset signal. It is explanatory drawing which shows the 2nd table for setting a coefficient according to a 1st table. It is explanatory drawing which shows the 1st table of the other example for setting a coefficient according to transmission power Pout_Tx and the temperature of a communication apparatus. It is a block diagram which shows the structural example of the receiving system of the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the communication apparatus in 2nd Embodiment. It is a block diagram which shows the structural example of the communication apparatus of the 3rd Embodiment of this invention.

Embodiment 1. FIG.
A communication apparatus 100 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of a communication device 100 according to the first embodiment of this invention. As illustrated in FIG. 1, the communication device 100 according to the first embodiment of the present invention receives a signal transmitted from a transmission device 200. Communication apparatus 100 includes reception gain variable amplifier 110, analog-to-digital converter 120, reception waveform shaping filter 130, reception distortion compensation circuit 140, demodulator 150, memory 160, and control circuit 170. .

  The reception gain variable amplifier 110 amplifies a signal received and input by an antenna (not shown) in accordance with the reception intensity of the signal, and inputs the amplified signal to the AD converter 120. The AD converter 120 converts the analog signal input by the reception gain variable amplifier 110 into a digital signal and inputs the digital signal to the reception waveform shaping filter 130. The reception waveform shaping filter 130 shapes the input signal into a predetermined waveform. A signal shaped through the reception waveform shaping filter 130 is input to the reception distortion compensation circuit 140. The memory 160 stores in advance coefficients used for distortion compensation processing applied to the signal by the reception distortion compensation circuit 140. The reception distortion compensation circuit 140 reads a coefficient corresponding to an instruction from the control circuit 170 from the memory 160, and performs distortion compensation processing on the input signal using the read coefficient. The reception distortion compensation circuit 140 inputs the signal subjected to the distortion compensation processing to the demodulator 150. Demodulator 150 demodulates the input signal and outputs the demodulated signal to the outside of communication apparatus 100. Demodulator 150 inputs the demodulated signal to reception distortion compensation circuit 140 and control circuit 170. The control circuit 170 instructs the reception distortion compensation circuit 140 on the coefficient to be read from the memory 160 based on the signal strength information indicating the strength of the signal output from the transmission device 200 included in the demodulated signal. In addition, the control circuit 170 measures the strength of the signal received by the antenna. Then, based on the preset value and the value of the signal strength measurement result, the control circuit 170 transmits transmission power control information for requesting transmission power control to the transmission apparatus 200 via the antenna. .

  The configuration of the transmission device 200 will be described. As illustrated in FIG. 1, the transmission apparatus 200 includes a modulator 210, a transmission waveform shaping filter 220, a transmission distortion compensation circuit 230, a DA (Digital to Analog) converter 240, and a transmission gain variable amplifier 250.

  The modulator 210 modulates the signal input to the transmission apparatus 200 by a predetermined modulation method that can be demodulated by the demodulator 150 of the communication apparatus 100 and inputs the modulated signal to the transmission waveform shaping filter 220. The transmission waveform shaping filter 220 shapes the input signal into a predetermined waveform. The signal shaped by passing through the transmission waveform shaping filter 220 is input to the transmission distortion compensation circuit 230. The transmission distortion compensation circuit 230 performs distortion compensation processing on the input signal using a preset coefficient. Then, the transmission distortion compensation circuit 230 inputs the signal subjected to the distortion compensation process to the DA converter 240. The DA converter 240 converts the digital signal input by the transmission distortion compensation circuit 230 into an analog signal and inputs the analog signal to the transmission gain variable amplifier 250. The transmission gain variable amplifier 250 amplifies the signal input by the DA converter 240 to the transmission power according to the instruction from the control circuit 170 of the communication apparatus 100 and inputs the amplified signal to an antenna (not shown). The signal input to the antenna is transmitted.

  The transmission device 200 has a reception function, for example, and when the antenna receives transmission power control information generated and transmitted by the control circuit 170 of the communication device 100, the transmission power control information is variable in transmission gain. Input to the amplifier 250. Then, the transmission gain variable amplifier 250 controls the amplification factor of the signal according to the request indicated by the transmission power control information.

  Next, the operation of the communication device 100 according to the first embodiment of this invention will be described. FIG. 2 is a flowchart showing operations of the reception distortion compensation circuit 140 and the control circuit 170 in the communication apparatus 100 according to the first embodiment of the present invention.

  As shown in FIG. 2, in the communication device 100 according to the first embodiment of the present invention, the control circuit 170 first reads signal strength information indicating the strength of the signal output from the transmission device 200 from the demodulated signal. (Step S101). In this example, it is assumed that the signal strength information indicates a transmission power value Pout_Tx.

  The control circuit 170 measures the strength of the signal received by the antenna. Then, the control circuit 170 compares the measured signal strength RSL (Received Signal Level) with a preset signal strength T_RSL (Target RSL) (step S102).

  If RSL = T_RSL (Y in step S102), the process proceeds to step S105. When RSL = T_RSL is not satisfied (N in step S102), the control circuit 170 calculates the difference ΔP (step S103).

In addition,
Difference ΔP = RSL−T_RSL (1)
It is. For example, when RSL = −40 dBm and T_RSL = −50 dBm, ΔP = + 10 dBm is calculated based on equation (1).

  The control circuit 170 transmits transmission power control information for requesting transmission power control to the transmission apparatus 200 via the antenna according to ΔP calculated based on the expression (1) in the process of step S103 (step S104). . When ΔP = + 10 dBm is calculated, the control circuit 170 generates transmission power control information indicating a request for reducing the transmission power by 10 dB, and transmits the transmission power control information to the transmission apparatus 200 via the antenna. The transmission gain variable amplifier 250 of the transmission apparatus 200 controls the transmission power according to the request indicated by the transmitted transmission power control information. In this example, the transmission gain variable amplifier 250 decreases the transmission power by 10 dB from the previous transmission power.

  Further, the control circuit 170 instructs the reception distortion compensation circuit 140 to read out a coefficient corresponding to the transmission power value Pout_Tx indicated by the signal strength information read out in the process of step S101 from the memory 160 (step S105). The reception distortion compensation circuit 140 reads the coefficient according to the instruction from the control circuit 170 from the memory 160 when the coefficient according to the instruction from the control circuit 170 is different from the coefficient read out last time (N in step S106) (step S107). ). Then, the reception distortion compensation circuit 140 applies the coefficient read from the memory 160 in the process of step S107 (step S108).

  The reception distortion compensation circuit 140 performs the following process when the coefficient according to the instruction from the control circuit 170 is the same as the coefficient read in the previous process in step S106 (Y in step S106). That is, the reception distortion compensation circuit 140 adjusts the coefficient read and applied from the memory 160 in the previous processing of steps S107 and S108 based on the demodulated signal input by the demodulator 110 (step S109). That is, the reception distortion compensation circuit 140 adjusts the coefficient read and applied from the memory 160 in the previous processing of steps S107 and S108 by feedback control.

  FIG. 3 is an explanatory diagram illustrating an example of coefficients stored in the memory 160. In the example illustrated in FIG. 3, a coefficient and an index are set for each of the transmission power values Pout_Tx of +30 to −5 dBm. In the example shown in FIG. 3, the coefficients are set in 1 dBm steps, but the coefficients may be set in finer steps, or the coefficients may be set in coarser steps. Further, the steps for setting the coefficients may be different from each other according to the range of the transmission power value Pout_Tx. Specifically, for example, coefficients may be set in 2 dBm steps for transmission power values Pout_Tx of +30 to +20 dBm and +10 to −5 dBm, and coefficients may be set in steps of 0.5 dBm for +20 to +10 dBm. . When the coefficient corresponding to the transmission power value Pout_Tx indicated by the signal strength information is not stored in the memory 160, the reception distortion compensation circuit 140, for example, transmits power having a value close to the transmission power value Pout_Tx indicated by the signal strength information. A coefficient corresponding to the value Pout_Tx is read from the memory 160 and applied. In addition, when there are a plurality of values that are the same as the transmission power value Pout_Tx indicated by the signal strength information, the reception distortion compensation circuit 140 obtains a coefficient corresponding to the smaller transmission power value Pout_Tx from the memory 160, for example. Read and apply.

  FIG. 4 is an explanatory diagram illustrating an example of a change in the transmission power value Pout_Tx indicated by the signal strength information and an index change in accordance with the coefficient read from the memory 160 according to the transmission power value Pout_Tx. FIG. 4A shows a change in the transmission power value Pout_Tx indicated by the signal strength information. In the example shown in FIG. 4A, the transmission power value Pout_Tx indicated by the signal strength information is decreased. FIG. 4B shows a change in index according to a coefficient read from the memory 160 according to a change in the transmission power value Pout_Tx indicated by the signal strength information. Further, as illustrated in FIG. 3, the memory 160 stores an index having a smaller value in association with a larger transmission power value Pout_Tx. Then, as illustrated in FIG. 4A, when the transmission power value Pout_Tx indicated by the signal strength information decreases, the index value associated with the coefficient read from the memory 160 as illustrated in FIG. 4B. Will increase. Then, the reception distortion compensation circuit 140 reads out and applies the coefficient associated with the index corresponding to the decrease in the transmission power value Pout_Tx indicated by the signal strength information.

  FIG. 5 is a block diagram illustrating a configuration example for adjusting the coefficients read and applied from the memory 160 in the process of step S108. In the example illustrated in FIG. 5, the reception distortion compensation circuit 140 includes an adder 141, a least square error calculator 142, a Volterra filter 143, and a modulator 144.

  In the Volterra filter 143 illustrated in FIG. 5, the coefficient of the first-order Volterra kernel, the coefficient of the third-order Volterra kernel, and the coefficient of the fifth-order Volterra kernel are set in the Volterra series expanded function. Yes. The coefficient of the first-order Volterra nucleus, the coefficient of the third-order Volterra nucleus, and the coefficient of the fifth-order Volterra nucleus are coefficients read from the memory 160 in the process of step S106. In other words, in the memory 160 of this example, the coefficient of the first-order Volterra kernel, the coefficient of the third-order Volterra kernel, and the coefficient of the fifth-order Volterra kernel are associated with the index and the transmission power value Pout_Tx. Is remembered.

  The signal input to the Volterra filter 143 is applied to the coefficient of the first-order Volterra kernel. Further, the signal input to the Volterra filter 143 is applied to the coefficient of the third-order Volterra kernel and the coefficient of the fifth-order Volterra kernel with a delay of d time. The Volterra filter 143 outputs a signal obtained by applying each coefficient to the input signal and inputs the signal to the demodulator 150 and the adder 141.

  The demodulator 150 demodulates the input signal. The demodulator 150 outputs the demodulated signal to the outside of the communication apparatus 100 and also to the modulator 144. Modulator 144 modulates the signal demodulated by demodulator 150 in a modulation scheme similar to the modulation scheme in modulator 210, that is, the signal before demodulation by demodulator 150. Then, the modulator 144 negatively feeds back the modulated signal to the adder 141.

  The adder 141 adds the signal that is negatively fed back via the modulator 144 to the signal that has passed through the Volterra filter 143, and inputs the addition result to the least square error calculator 142. The least square error calculator 142 adjusts the first-order Volterra kernel coefficient, the third-order Volterra kernel coefficient, and the fifth-order Volterra kernel coefficient so that the absolute value of the addition result value becomes smaller. .

  FIG. 6 is an explanatory diagram showing a change in the absolute value of the addition result by the adder 141. In FIG. 6, the change in error, which is the result of addition by the adder 141 according to this example, is indicated by a solid line. As indicated by the solid line in FIG. 6, after a new coefficient is set, the coefficient is adjusted in the process of step S <b> 108, thereby reducing the absolute value of the value resulting from the addition by the adder 141. Recognize. Further, in FIG. 6, a change in the addition result by the adder 141 when a predetermined coefficient is set regardless of the transmission power value Pout_Tx is indicated by a broken line. As shown in FIG. 6, when the coefficient is set according to the transmission power value Pout_Tx as in the present embodiment, it is faster than the case where a predetermined coefficient is set regardless of the transmission power value Pout_Tx. In addition, the absolute value of the addition result by the adder 141 can be made close to zero. Therefore, the distortion compensation by the reception distortion compensation circuit 104 can be performed quickly and accurately.

  According to the present embodiment, the control circuit 170 of the communication apparatus 100 transmits transmission power control information for requesting control of transmission power based on a preset value and a value of a signal strength measurement result. To device 200. Therefore, transmission power control information corresponding to the influence of nonlinear distortion of a signal generated during propagation between the transmission apparatus 200 and the communication apparatus 100 is transmitted to the transmission apparatus 200. Then, the reception distortion compensation circuit 140 of the communication apparatus 100 performs distortion compensation processing by applying a coefficient corresponding to the intensity of the signal output from the transmission apparatus 200 according to the transmission power control information. Therefore, the distortion compensation processing performed by the reception distortion compensation circuit 140 of the communication apparatus 100 can satisfactorily suppress the influence due to nonlinear distortion of a signal generated during propagation between the transmission apparatus 200 and the communication apparatus 100.

  Note that the distortion of signals transmitted and received in communication apparatus 100 and transmission apparatus 200 depends on reception gain (in the configuration having an automatic gain control function, RSL and a preset signal strength T_RSL in addition to transmission power). Or is affected by the temperature of the device. FIG. 7 is an explanatory diagram illustrating an example of a first table for setting coefficients according to transmission power Pout_Tx and a preset signal strength T_RSL. FIG. 8 is an explanatory diagram showing a second table for setting coefficients according to the first table. Note that it is assumed that the first table shown in FIG. 7 and the second table shown in FIG.

  In the example shown in FIG. 7, the transmission power Pout_Tx, a preset signal strength T_RSL, and a coefficient index are associated with each other. Specifically, the index (1, 1) is associated with Pout_Tx of +30 dBm and T_RSL of −20 dBm.

  In the example shown in FIG. 8, coefficients (a1, 1, b1, 1, c1, 1,...) Are associated with the index (1, 1).

  In this example, the control circuit 170 stores, for example, the transmission power value Pout_Tx indicated by the signal strength information read out in the process of step S101 and an index corresponding to the preset signal strength T_RSL in the memory 160. Read from the first table. Then, the control circuit 170 instructs the reception distortion compensation circuit 140 to read out the coefficient corresponding to the index read from the first table of the memory 160 from the second table stored in the memory 160. The reception distortion compensation circuit 140 performs distortion compensation processing using the coefficient read from the second table of the memory 160 according to the instruction.

  According to such a configuration, it is possible to perform distortion compensation processing with higher accuracy than in the case where a coefficient corresponding to only the transmission power value Pout_Tx is used.

  FIG. 9 is an explanatory diagram illustrating a first table of another example for setting a coefficient in accordance with transmission power Pout_Tx and the temperature of the communication device 100. In the example illustrated in FIG. 9, the transmission power Pout_Tx, the temperature of the communication device 100, and the coefficient index are associated with each other. Specifically, the index (1, 1) is associated with Pout_Tx of +30 dBm and the temperature of the communication device 100 of −40 ° C.

  In this example, the control circuit 170 stores, for example, an index according to the transmission power value Pout_Tx indicated by the signal strength information read out in the process of step S101 and the temperature of the communication device 100 measured by a thermometer (not shown). Read from the first table of another example stored in 160. Then, the control circuit 170 instructs the reception distortion compensation circuit 140 to read out the coefficient corresponding to the index read from the first table of another example of the memory 160 from the second table of the memory 160. The reception distortion compensation circuit 140 performs distortion compensation processing using the coefficient read from the second table of the memory 160 according to the instruction.

  According to such a configuration, it is possible to perform distortion compensation processing with higher accuracy than in the case where a coefficient corresponding to only the transmission power value Pout_Tx is used.

Embodiment 2. FIG.
Next, a reception system 300 according to the second embodiment of this invention will be described. FIG. 10 is a block diagram illustrating a configuration example of the reception system 300 according to the second embodiment of this invention. As illustrated in FIG. 10, the reception system 300 according to the second embodiment of the present invention includes a communication device 102 and a communication device 103 that receive a signal from the transmission device 200. The reception system 300 is configured to receive a signal from the transmission device 200 by a diversity reception method by the communication device 102 and the communication device 103, or to be configured to be redundant and support hot standby.

  FIG. 11 is a block diagram illustrating a configuration example of the communication apparatus 102 according to the present embodiment. Note that the configuration of the communication device 103 is the same as the configuration example of the communication device 102 illustrated in FIG. 11.

  The communication device 102 illustrated in FIG. 11 is different from the configuration in the communication device 100 illustrated in FIG. 10 in that the control circuit 172 transmits and receives information indicating coefficients to and from the control circuit in the communication device 103. Other configurations are the same as those in the communication apparatus 100 shown in FIG. 10, and thus the same reference numerals as those in FIG.

  When the control circuit 172 instructs the reception distortion compensation circuit 140 to read out the coefficient from the memory 160, the control circuit 172 notifies the communication apparatus 103 of information indicating the coefficient. In addition, when information indicating a coefficient is notified from the communication apparatus 103, the control circuit 172 instructs the reception distortion compensation circuit 140 to read out the coefficient indicated by the information from the memory 160.

  According to this embodiment, the operating communication device notifies the standby communication device of the coefficient. Then, the standby communication apparatus applies the notified coefficient to the reception distortion compensation circuit. Therefore, when the communication device to be operated is switched to the standby communication device, the coefficient is already applied to the reception distortion compensation circuit of the standby communication device. Therefore, according to this embodiment, in addition to the effect of 1st Embodiment, there can exist an effect that the standby communication apparatus can be started rapidly.

Embodiment 3. FIG.
Next, a communication device according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a block diagram illustrating a configuration example of the communication device 10 according to the third embodiment of this invention. As shown in FIG. 12, the communication device 10 according to the third embodiment of the present invention includes a storage unit 16, a control unit 17, and a distortion compensation circuit 14. The storage unit 16 corresponds to the memory 160 shown in FIG. The control means 17 corresponds to the control circuit 170 shown in FIG. The distortion compensation circuit 14 corresponds to the reception distortion compensation circuit 140 shown in FIG.

  The storage unit 16 stores a coefficient to be applied to the distortion compensation circuit 14 that performs distortion compensation processing on the signal.

  The control unit 17 requests the transmission side to control the transmission power according to the strength of the received signal, and instructs the distortion compensation circuit 14 to read out and apply the coefficient from the storage unit 16 according to the transmission power on the transmission side.

  The distortion compensation circuit 14 reads out a coefficient corresponding to an instruction from the control means 17 from the storage means 16 and performs distortion compensation processing on the signal based on the received signal using the read coefficient.

  According to the present embodiment, it is possible to satisfactorily suppress the influence of nonlinear distortion of a signal generated during propagation or the like.

DESCRIPTION OF SYMBOLS 10, 100, 102, 103 Communication apparatus 14 Distortion compensation circuit 16 Memory | storage means 17 Control means 110 Reception gain variable amplifier 120 AD converter 130 Reception waveform shaping filter 140 Reception distortion compensation circuit 141 Adder 142 Least square error calculator 143 Volterra filter 144 Modulator 150 Demodulator 160 Memory 170, 172 Control circuit 200 Transmitting device 210 Modulator 220 Transmission waveform shaping filter 230 Transmission distortion compensation circuit 240 DA converter 250 Transmission gain variable amplifier 300 Reception system

Claims (7)

Storage means for storing a coefficient to be applied to a distortion compensation circuit that performs distortion compensation processing on a signal;
Control means for requesting the transmission side to control transmission power in accordance with the intensity of the received signal, and instructing the distortion compensation circuit to apply a coefficient to be read from the storage means in accordance with the transmission power on the transmission side;
And a distortion compensation circuit that reads out the coefficient according to an instruction from the control means from the storage means, and performs the distortion compensation processing on a signal based on the received signal using the read coefficient. apparatus. The storage means stores a coefficient according to the transmission power and the intensity of the received signal,
The communication apparatus according to claim 1, wherein the control unit instructs the distortion compensation circuit to determine a coefficient to be read and applied from the storage unit according to the transmission power and the strength of the received signal. The storage means stores a coefficient according to the transmission power and the temperature of the communication device,
The communication apparatus according to claim 1, wherein the control means instructs the distortion compensation circuit to apply a coefficient read from the storage means and applied in accordance with the transmission power and the temperature of the communication apparatus. The storage means stores a coefficient in a Volterra series expanded function,
The communication apparatus according to claim 1, wherein the distortion compensation circuit includes a Volterra filter that performs distortion compensation processing on a signal based on the received signal using the coefficient. Including a plurality of communication devices according to any one of claims 1 to 4,
When each of the control means of the plurality of communication devices instructs the distortion compensation circuit to read and apply a coefficient to be read from the storage means, the information indicating the coefficient is notified to the other communication apparatus. When the information indicating the coefficient is notified from, the communication system is configured to instruct the distortion compensation circuit of the communication apparatus to read and apply the coefficient from the storage unit. The communication system according to claim 5, comprising the transmission device on the transmission side. A coefficient to be applied to a distortion compensation circuit that requests transmission power control on the transmission side according to the intensity of the received signal, and that reads out from the storage means and performs distortion compensation processing on the signal according to the transmission power on the transmission side. A control step for instructing the distortion compensation circuit;
A distortion compensation step of reading out the coefficient corresponding to the instruction in the control step from the storage unit, and causing the distortion compensation circuit to perform the distortion compensation processing on the signal using the read coefficient. A distortion compensation method.

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