Patent Description:
A power amplifier (PA) used for a radio frequency (RF) end in a wireless communication system may have nonlinear characteristics. To compensate for such nonlinear characteristics, digital predistortion (DPD) may be performed on a signal before the signal is input to the PA. By DPD, an output signal of the PA may have linear characteristics.

Meanwhile, a communication device may include a receiver, and the receiver may include a plurality of analog-to-digital converters (ADCs) operating at high speed. When a DPD parameter is updated, the receiver may operate as an observation receiver. When the receiver operates as an observation receiver, all the ADCs may operate at high speed, consuming a lot of power.

<CIT>discloses a method and system for power amplifier characterization and digital predistortion. The method includes receiving a test signal including K samples with a sampling rate Fs, generating a synthetic test signal including the test signal and a sequence of (N-<NUM>) delayed versions of the test signal, generating an under sampled signal including M samples by sampling, at a sampling rate Fs/N, an output signal of a device-under-test (DUT) with the synthetic test signal as an input of the DUT, the M samples of the undersampled signal including N segments each including K/N samples, and generating a reconstructed signal including the M samples of the under sampled signal.

<CIT> discloses an amplifier system may include a predistorter receiving an input signal to generate a predistortion signal, a first converter receiving the predistortion signal to generate a preamplified signal, a power amplifier receiving the preamplified signal to generate an output signal based on the preamplified signal and the input signal, and a second converter sampling the output signal to generate a feedback signal. The power amplifier may produce a distortion signal at a first frequency. The second converter may sample the output signal using a timing signal with a second frequency that is lower than the first frequency to generate the feedback signal, and the predistorter, based upon the feedback signal, may predistort the predistortion signal to reduce the distortion signal at the first frequency.

According to various embodiments, provided may be a communication device for using a receiver as an observation receiver when updating a digital predistortion (DPD) parameter while achieving power saving by turning on one or more of analog-to-digital converters (ADCs) in the receiver and turning off the remaining ADCs.

According to various embodiments, provided may be a communication device that includes an observation receiver distinct from a receiver and is capable of high-speed processing through ADCs in the observation receiver.

According to various embodiments, it is possible to use a receiver as an observation receiver when updating a digital predistortion (DPD) parameter while achieving power saving by turning on one or more of analog-to-digital converters (ADCs) in the receiver and turning off the remaining ADCs.

According to various embodiments, a wideband ADC in an observation receiver distinct from a receiver may be inexpensive and more cost-effective, operate at high speed, and be capable of high-speed processing when updating a DPD parameter.

In addition, various effects directly or indirectly ascertained through the present disclosure may be provided.

When describing the embodiments with reference to the accompanying drawings, like reference numerals refer to like elements and a repeated description related thereto will be omitted.

<FIG> is an exemplary diagram illustrating a communication device according to various embodiments.

Referring to <FIG>, a communication device <NUM> may include a transmitter <NUM>, a processor <NUM>, and a receiver <NUM>.

According to an embodiment, the communication device <NUM> may be included in an electronic device (e.g., a smartphone or a tablet personal computer (PC)) and may communicate with an external device (e.g., a base station device). According to another embodiment, the communication device <NUM> may be included in a base station device (e.g., a radio unit (RU)) and may communicate with an external device (e.g., an electronic device such as a mobile terminal).

According to an embodiment, the communication device <NUM> may perform communication using a time division duplex (TDD) scheme. According to another embodiment, the communication device <NUM> may perform communication using a frequency division duplex (FDD) scheme. According to still another embodiment, the communication device <NUM> may perform communication using a scheme in which the TDD scheme and the FDD scheme are combined.

According to an embodiment, the transmitter <NUM> may receive a baseband signal (e.g., a baseband digital in-phase (I) quadrature-phase (Q) stream) from a modem (not shown), convert the received baseband signal into a radio frequency (RF) signal, and transmit the RF signal to an external device through an antenna.

According to an embodiment, the receiver <NUM> may convert the RF signal received through an antenna into the baseband signal and transmit the baseband signal to a modem.

The processor <NUM> may control the communication device <NUM> overall.

According to an embodiment, the processor <NUM> may perform a digital predistortion (DPD) parameter update operation. In the DPD parameter update operation, the processor <NUM> may cause a portion of a plurality of analog-to-digital converters (ADCs) in the receiver <NUM> to be turned on and the remaining ADCs in the receiver <NUM> to be turned off. This will be described later with reference to <FIG>.

<FIG> is an exemplary diagram illustrating a transmission operation of a communication device according to various embodiments.

Referring to <FIG>, the transmitter <NUM> may include a DPD unit <NUM>, a first conversion unit <NUM>, an upconverter <NUM>, a power amplifier (PA) <NUM>, a coupler <NUM>, and a transmission antenna <NUM>.

The receiver <NUM> may include a reception antenna <NUM>, a low-noise amplifier (LNA) <NUM>, a downconverter <NUM>, and a second conversion unit <NUM>.

In the example shown in <FIG>, the transmission antenna <NUM> and the reception antenna <NUM> may be the same antenna. In other words, an antenna may operate as the transmission antenna <NUM> for transmitting an RF signal to the outside in a transmission operation and may operate as the reception antenna <NUM> for receiving an RF signal in a reception operation. In the transmission operation, the PA <NUM> and the antenna may be electrically connected through a TX/RX switch (not shown), so that the antenna may operate as the transmission antenna <NUM>. In the reception operation, the LNA <NUM> and the antenna may be electrically connected through a TX/RX switch (not shown), so that the antenna may operate as the reception antenna <NUM>. Depending on the implementation, the transmission antenna <NUM> and the reception antenna <NUM> may be physically distinct.

An example of the operation of the communication device <NUM> in the transmission operation is shown in <FIG>. The communication device <NUM> may perform the reception operation, and an example of the reception operation will be described with reference to <FIG>.

In the example shown in <FIG>, the DPD unit <NUM> may distort an input signal (e.g., a baseband signal from a modem). This distortion may be performed before the amplification operation of the PA <NUM> and may thus be referred to as "predistortion". The distorted input signal may be input to the first conversion unit <NUM>.

The first conversion unit <NUM> may include one or more digital-to-analog converters (DACs). The first conversion unit <NUM> may convert the distorted input signal into an analog signal.

The upconverter <NUM> may generate an RF signal by performing frequency up-conversion on the converted analog signal. The RF signal may be input to the PA <NUM>.

The PA <NUM> may amplify the power of the generated RF signal.

In the transmission operation, the coupler <NUM> may not couple the amplified RF signal and may transmit the amplified RF signal to the transmission antenna <NUM>.

The transmission antenna <NUM> may transmit the amplified RF signal to an external device.

<FIG> and <FIG> are exemplary diagrams illustrating a reception operation of a communication device according to various embodiments.

In the example shown in <FIG>, the reception antenna <NUM> may receive an RF signal from an external device.

The LNA <NUM> may amplify the received RF signal and may remove or minimize the noise in the received RF signal. An output signal of the LNA <NUM> may be input to the downconverter <NUM>.

The downconverter <NUM> may perform frequency down-conversion on the output signal of the LNA <NUM>. An output signal of the downconverter <NUM> may be input to the second conversion unit <NUM>.

The second conversion unit <NUM> may include one or more ADCs. The second conversion unit <NUM> may convert the output signal of the downconverter <NUM> into a digital signal and transmit the digital signal to a modem.

An example of the second conversion unit <NUM> is shown in <FIG>. In the example shown in <FIG>, the second conversion unit <NUM> may include a plurality of ADCs <NUM>-<NUM> to <NUM>-n, a demultiplexer (DEMUX) <NUM>, and a multiplexer (MUX) <NUM>.

Each of the plurality of ADCs <NUM>-<NUM> to <NUM>-n may include a sample (S)/hold (H) circuit for sampling an input signal.

In the example shown in <FIG>, the ADCs <NUM>-<NUM> to <NUM>-n may be time-interleaved ADCs. The time-interleaved ADCs <NUM>-<NUM> to <NUM>-n may generate digital signals by alternately sampling and digitizing the output signal of the downconverter <NUM>. For example, the DEMUX <NUM> may transmit the output signal of the downconverter <NUM> to the first ADC <NUM>-<NUM> by connecting an input terminal of the first ADC <NUM>-<NUM> and an output terminal of the downconverter <NUM>, and the first ADC <NUM>-<NUM> may convert an output signal of the downconverter <NUM> into a digital signal. The DEMUX <NUM> may transmit the output signal of the downconverter <NUM> to the second ADC <NUM>-<NUM> by connecting an input terminal of the second ADC <NUM>-<NUM> and the output terminal of the downconverter <NUM>, and the second ADC <NUM>-<NUM> may convert the output signal of the downconverter <NUM> into a digital signal. The DEMUX <NUM> may transmit the output signal of the downconverter <NUM> to the n-th ADC <NUM>-n by connecting an input terminal of the n-th ADC <NUM>-n and the output terminal of the downconverter <NUM>, and the n-th ADC <NUM>-n may convert the output signal of the downconverter <NUM> into a digital signal.

The MUX <NUM> may multiplex (or combine) the digital signals converted respectively by the time-interleaved ADCs <NUM>-<NUM> to <NUM>-n and transmit a digital signal obtained by multiplexing to a modem.

<FIG> are exemplary diagrams illustrating power saving in a digital predistortion (DPD) parameter update operation of a communication device according to various embodiments.

In the example shown in <FIG>, the communication device <NUM> may perform a DPD parameter update operation. In the DPD parameter update operation, the receiver <NUM> may operate as an observation receiver for observing an output signal of the PA <NUM> of the transmitter <NUM>. The DPD parameter update operation may also be referred to as an observation operation.

ADCs <NUM>-<NUM> to <NUM>-n in the second conversion unit <NUM> may each perform digitization at a high frequency (e.g., <NUM> gigahertz (GHz)) and may operate at high speed, consuming a lot of power. According to an embodiment, in the DPD parameter update operation, the processor <NUM> may achieve power saving by causing one or more of the ADCs <NUM>-<NUM> to <NUM>-n to be turned on and the remaining ADCs to be turned off.

According to an embodiment, the PA <NUM> may have nonlinear characteristics due to a memoryless effect. The memoryless effect may indicate that the current input signal of the PA <NUM> affects the output signal of the PA <NUM>. The DPD unit <NUM> may be implemented to compensate for the nonlinear characteristics due to the memoryless effect. In this case, the processor <NUM> may turn on one of the ADCs <NUM>-<NUM> to <NUM>-n and turn off the remaining ADCs. The remaining ADCs may be turned off, such that power saving may be achieved.

According to another embodiment, the PA <NUM> may have nonlinear characteristics due to a memory effect. The memory effect may indicate that previous input signals as well as the current input signal of the PA <NUM> affect the output signal of the PA <NUM>. The DPD unit <NUM> may be implemented to compensate for the nonlinear characteristics due to the memory effect. In this case, the processor <NUM> may turn on two or more of the ADCs <NUM>-<NUM> to <NUM>-n and turn off the remaining ADCs. The remaining ADCs may be turned off, such that power saving may be achieved.

In the example shown in <FIG>, the DPD unit <NUM> may distort an input signal x̃[n] (e.g., a baseband signal received from a modem). An output signal of the DPD unit <NUM> may be input to the first conversion unit <NUM>. The processor <NUM> may obtain (or capture) the input signal x̃[n] of the DPD unit <NUM>.

According to an embodiment, the transmitter <NUM> may further include a crest factor reduction (CFR) unit (not shown) for performing CFR on the input signal x̃[n]. For example, the CFR unit may verify the peak power of the input signal x̃[n], and may cause the processor <NUM> to capture the input signal x̃[n] when the verified peak power exceeds a threshold. In other words, the CFR unit may trigger the processor <NUM> to capture the input signal x̃[n] when the peak power of the input signal x̃[n] exceeds the threshold value.

The first conversion unit <NUM> may convert the output signal of the DPD unit <NUM> into an analog signal.

The upconverter <NUM> may perform frequency up-conversion on the converted analog signal to generate an RF signal. The RF signal may be input to the PA <NUM>.

The PA <NUM> may amplify the power of the input RF signal. The amplified RF signal may be transmitted to the coupler <NUM>.

The coupler <NUM> may couple the amplified RF signal. For example, the coupler <NUM> may couple a portion of the amplified RF signal, transmit the coupled portion of the RF signal to the downconverter <NUM>, and transmit the remaining portion to the transmission antenna <NUM>.

The downconverter <NUM> may perform frequency down-conversion on the coupled RF signal y(t). An output signal y<NUM>(t) of the downconverter <NUM> may be transmitted to the second conversion unit <NUM>.

The second conversion unit <NUM> may convert the output signal y<NUM>(t) into a digital signal ỹ[n] and transmit the digital signal ỹ[n] to the processor <NUM>. The operation of the second conversion unit <NUM> will be described with reference to <FIG> and <FIG>.

An example of the operation of the second conversion unit <NUM>, when the DPD unit <NUM> is implemented to compensate for the nonlinear characteristics of the PA <NUM> due to the memoryless effect, is shown in <FIG>.

In the example shown in <FIG>, the DPD unit <NUM> may be implemented to compensate for the nonlinear characteristics of the PA <NUM> due to the memoryless effect, so that in the DPD parameter update operation, one ADC may be turned on, and the remaining ADCs may be turned off. For example, the processor <NUM> may cause the first ADC <NUM>-<NUM> among the plurality of ADCs <NUM>-<NUM> to <NUM>-n to be turned on. The remaining ADCs <NUM>-<NUM> to <NUM>-n may be turned off.

In the example shown in <FIG>, the DEMUX <NUM> may transmit the output signal y<NUM>(t) of the downconverter <NUM> to the first ADC <NUM>-<NUM> by connecting the input terminal of the first ADC <NUM>-<NUM> and the output terminal of the downconverter <NUM>. The DEMUX <NUM> may not connect the input terminal of each of the remaining ADCs <NUM>-<NUM> to <NUM>-n to the output terminal of the downconverter <NUM>.

In the example shown in <FIG>, the first ADC <NUM>-<NUM> may convert the input signal y<NUM>(t) into a digital signal ỹ[n] and transmit the digital signal ỹ[n] to the MUX <NUM>.

The MUX <NUM> may transmit the digital signal ỹ[n] to the processor <NUM>.

In the example shown in <FIG>, the processor <NUM> may determine a DPD parameter based on the input signal x̃[n] and the digital signal ỹ[n] and control the DPD unit <NUM> based on the determined DPD parameter. The DPD parameter may include, for example, a coefficient of a first DPD function of the DPD unit <NUM>. The first DPD function may include, for example, a function to approximate the inversion of a first model that models the nonlinear characteristics of the PA <NUM> due to the memoryless effect. According to an embodiment, the processor <NUM> may calculate the coefficient of the first DPD function of the DPD unit <NUM> using the input signal x̃[n] and the digital signal ỹ[n] and transmit the calculated coefficient to the DPD unit <NUM>. The DPD unit <NUM> may update the existing coefficient of the first DPD function with the coefficient received from the processor <NUM> and perform distortion based on the first DPD function with the coefficient updated.

An example of the operation of the second conversion unit <NUM>, when the DPD unit <NUM> is implemented to compensate for the nonlinear characteristics of the PA <NUM> due to the memory effect, is shown in <FIG>.

In the example shown in <FIG>, the DPD unit <NUM> may store or include a second DPD function for distortion. The second DPD function may include, for example, a function to approximate the inversion of a second model that models the nonlinear characteristics of the PA <NUM> due to the memory effect. Equation <NUM> below shows a memory polynomial model that is an example of the second model. The second model is not limited to the memory polynomial model in Equation <NUM> below.

In Equation <NUM> above, x(n) may denote the input signal of the PA <NUM> expressed as a discrete signal, and y(n) may denote the output signal (or the coupled RF signal y(t)) of the PA <NUM> expressed as a discrete signal. Further, in Equation <NUM> above, k may denote a polynomial order, M may denote a memory order, and bkm may denote the coefficient of the memory polynomial model.

According to an embodiment, when the DPD unit <NUM> is implemented to compensate for the nonlinear characteristics of the PA <NUM> due to the memory effect, the number of ADCs to be turned on in the DPD parameter update operation is determined based on the memory order of the second model. As an example, if the memory order is "<NUM>", two ADCs may be turned on in the DPD update operation. As another example, if the memory order is "<NUM>", three ADCs may be turned on in the DPD update operation.

In the example shown in <FIG>, the memory order of the second model may be "<NUM>". In the DPD update operation, two ADCs (e.g., the first ADC <NUM>-<NUM> and the second ADC <NUM>-<NUM>) may be turned on, and the remaining ADCs <NUM>-<NUM> to <NUM>-n may be turned off. According to an embodiment, which of the ADCs <NUM>-<NUM> to <NUM>-n is to be turned on in the DPD update operation may be pre-designated. In the case of the example shown in <FIG>, the first ADC <NUM>-<NUM> and the second ADC <NUM>-<NUM> may be pre-designated to be turned on in the DPD update operation. In the DPD update operation, the first ADC <NUM>-<NUM> and the second ADC <NUM>-<NUM> may be turned on, and the remaining ADCs <NUM>-<NUM> to <NUM>-n may be turned off. According to another embodiment, the processor <NUM> may randomly select which of the ADCs <NUM>-<NUM> to <NUM>-n to be turned on in the DPD update operation. The processor <NUM> may randomly select the first ADC <NUM>-<NUM> and the second ADC <NUM>-<NUM>, so that in the DPD update operation, the first ADC <NUM>-<NUM> and the second ADC <NUM>-<NUM> may be turned on, and the remaining ADCs <NUM>-<NUM> to <NUM>-n may be turned off.

In the example shown in <FIG>, the DEMUX <NUM> may transmit the output signal y<NUM>(t) of the downconverter <NUM> to the first ADC <NUM>-<NUM> by connecting the input terminal of the first ADC <NUM>-<NUM> to the output terminal of the downconverter <NUM>. The first ADC <NUM>-<NUM> may convert the input signal into a digital signal ỹ<NUM>[n] and transmit the digital signal ỹ<NUM>[n] to the MUX <NUM>.

The DEMUX <NUM> may transmit the output signal y<NUM>(t) of the downconverter <NUM> to the second ADC <NUM>-<NUM> by connecting the input terminal of the second ADC <NUM>-<NUM> to the output terminal of the downconverter <NUM>. The second ADC <NUM>-<NUM> may convert the input signal into a digital signal ỹ<NUM>[n] and transmit the digital signal ỹ<NUM>[n] to the MUX <NUM>.

In the example shown in <FIG>, the DEMUX <NUM> may not connect the input terminal of each of the remaining ADCs <NUM>-<NUM> to <NUM>-n to the output terminal of the downconverter <NUM>.

In the example shown in <FIG>, the MUX <NUM> may multiplex the digital signal ỹ<NUM>[n] and the digital signal ỹ<NUM>[n] and output a digital signal ỹ[n] to the processor <NUM>. In other words, the MUX <NUM> may generate the digital signal ỹ[n] by combining the digital signal ỹ<NUM>[n] and the digital signal ỹ<NUM>[n] and transmit the digital signal ỹ[n] to the processor <NUM>.

In the example shown in <FIG>, the processor <NUM> may determine a DPD parameter based on the input signal x̃[n] and the digital signal ỹ[n] and control the DPD unit <NUM> based on the determined DPD parameter. The DPD parameter may include, for example, a coefficient of a second DPD function of the DPD unit <NUM>. As an example, the processor <NUM> may calculate the coefficient of the second DPD function of the DPD unit <NUM> using the input signal x̃[n] and the digital signal ỹ[n] and transmit the calculated coefficient to the DPD unit <NUM>. The DPD unit <NUM> may update the existing coefficient of the second DPD function with the coefficient received from the processor <NUM> and perform distortion based on the second DPD function with the coefficient updated.

According to an embodiment, the transmitter <NUM> may distort an input signal through the DPD unit <NUM>, convert the distorted input signal into an analog signal, perform frequency up-conversion on the converted analog signal to generate a first signal, amplify the generated first signal through the PA <NUM>, and couple the amplified first signal, in a first operation (e.g., the DPD parameter update operation).

According to an embodiment, in the first operation, the receiver <NUM> may receive the coupled first signal from the transmitter <NUM>, perform frequency down-conversion on the coupled first signal to generate a second signal, and convert the generated second signal into a digital signal through the turned-on one or more ADCs among the plurality of ADCs <NUM>-<NUM> to <NUM>-n.

According to an embodiment, in the first operation, the processor <NUM> may cause one or more of the ADCs <NUM>-<NUM> to <NUM>-n in the receiver <NUM> to be turned on and the remaining ADCs to be turned off.

According to an embodiment, the DPD unit <NUM> may include a function for distorting an input signal.

According to an embodiment, when the function for distorting the input signal is a function determined based on the inverse of a model that models the first nonlinear characteristics of the PA <NUM> (e.g., the first model described above), one ADC may be turned on in the first operation.

According to an embodiment, the first nonlinear characteristics may be the nonlinear characteristics due to a memoryless effect of the PA <NUM>.

According to an embodiment, when the function for distorting the input signal is a function determined based on the inverse of a model that models the second nonlinear characteristics of the PA <NUM> (e.g., the second model described above), the number of ADCs to be turned on in the first operation is determined based on the memory order of the model that models the second nonlinear characteristics of the PA <NUM>.

According to an embodiment, the second nonlinear characteristics may be the nonlinear characteristics due to a memory effect of the PA <NUM>.

According to an embodiment, in response to a change from the first operation to a second operation (e.g., a reception operation), the turned-off ADCs may be turned on, and in the second operation, the receiver <NUM> may convert a signal received through the antenna <NUM> into a digital signal through the turned-on ADCs.

According to an embodiment, the processor <NUM> may determine a predistortion parameter (e.g., the DPD parameter described above) using the converted digital signal and the input signal of the DPD unit <NUM> and control the DPD unit <NUM> using the determined predistortion parameter.

According to an embodiment, the receiver <NUM> may operate as an observation receiver for observing the transmitter <NUM> in the first operation.

According to an embodiment, the ADCs <NUM>-<NUM> to <NUM>-n may be time-interleaved.

<FIG> is another exemplary diagram illustrating a communication device according to various embodiments.

Referring to <FIG>, a communication device <NUM> may include a processor <NUM>, a transmitter <NUM>, an observation receiver <NUM>, and a receiver <NUM>.

The receiver <NUM> of the communication device <NUM> described with reference to <FIG> may perform a reception operation and operate as an observation receiver for observing the transmitter <NUM> in a DPD parameter update operation. The communication device <NUM> to be described with reference to <FIG> may include the observation receiver <NUM> which is distinct from the receiver <NUM> for performing the reception operation.

According to an embodiment, the communication device <NUM> may be included in an electronic device (e.g., a smartphone or a tablet personal computer (PC)) and may communicate with an external device (e.g., a base station device). According to another embodiment, the communication device <NUM> may be included in a base station device (e.g., an RU) and may communicate with an external device (e.g., an electronic device such as a mobile terminal).

According to an embodiment, in a transmission operation, the transmitter <NUM> may distort an input signal (e.g., a baseband signal received from a modem), convert the distorted input signal into an RF signal, amplify the converted RF signal, and transmit the amplified RF signal to an external device through an antenna.

According to an embodiment, in the reception operation, the receiver <NUM> may convert the RF signal received through an antenna into a baseband signal and transmit the baseband signal to a modem (not shown).

According to an embodiment, the communication device <NUM> may perform the DPD parameter update operation. In the DPD parameter update operation, the transmitter <NUM> may distort the input signal through a DPD unit (not shown), convert the distorted input signal into an RF signal, and amplify the converted RF signal. The processor <NUM> may capture the input signal of the transmitter <NUM>. The transmitter <NUM> may transmit or feed the amplified RF signal back to the observation receiver <NUM>. The observation receiver <NUM> may perform frequency down-conversion on the amplified RF signal received from the transmitter <NUM>, convert the frequency-down-converted RF signal into a digital signal through an ADC (not shown), and transmit the converted digital signal to the processor <NUM>.

According to an embodiment, the observation receiver <NUM> may include the ADC. The ADC in the observation receiver <NUM> may be a wideband ADC that operates in a wideband. The sampling time of the ADC in the observation receiver <NUM> may be less than "predetermined value/signal bandwidth". The predetermined value may be, for example, "<NUM>" but is not limited thereto. As an example, when the signal bandwidth for signal transmission of the transmitter <NUM> is <NUM>, the sampling time of the ADC in the observation receiver <NUM> may be less than "<NUM>" picoseconds (ps). The sampling frequency of the ADC in the observation receiver <NUM> may be less than "n times the signal bandwidth". Here, n may be "<NUM>" but is not limited thereto. The ADC in the observation receiver <NUM> may be less expensive than the ADCs (e.g., the plurality of ADCs <NUM>-<NUM> to <NUM>-n) used in the receiver <NUM> and may perform high-speed processing.

The processor <NUM> may determine a DPD parameter using the captured input signal and the digital signal received from the ADC in the observation receiver <NUM> and control the DPD unit in the transmitter <NUM> using the determined DPD parameter.

<FIG> is a diagram illustrating an example of a transmitter and an observation receiver in a communication device according to various embodiments.

Referring to <FIG>, a communication device <NUM> may include a processor <NUM>, a transmitter <NUM>, and an observation receiver <NUM>. Although not shown in <FIG>, the communication device <NUM> may include a receiver <NUM>. The transmitter <NUM> and the observation receiver <NUM> to be described with reference to <FIG> may correspond to an example of the transmitter <NUM> and an example of the observation receiver <NUM> of <FIG>, respectively. According to an embodiment, the structure of the transmitter <NUM> to be described with reference to <FIG> may apply to the transmitter <NUM> of <FIG>.

In the example shown in <FIG>, the transmitter <NUM> may include a DPD unit <NUM>, a first conversion unit <NUM>, an upconverter <NUM>, a splitter <NUM>, a plurality of blocks <NUM>-<NUM> to <NUM>-n, a plurality of PAs <NUM>-<NUM> to <NUM>-n, and a plurality of antennas <NUM>-<NUM> to <NUM>-n. The antennas <NUM>-<NUM> to <NUM>-n may form an array structure.

In the example shown in <FIG>, the observation receiver <NUM> may include an antenna <NUM>, a downconverter <NUM>, and an ADC <NUM>.

The DPD unit <NUM> may distort an input signal (e.g., a baseband digital signal received from a modem) and output the distorted input signal to the first conversion unit <NUM>. According to an embodiment, the DPD unit <NUM> may operate substantially the same as the DPD unit <NUM> of <FIG>.

The processor <NUM> may capture the input signal of the DPD unit <NUM>.

The first conversion unit <NUM> may include one or more DACs. The first conversion unit <NUM> may convert the distorted input signal into an analog signal and output the converted analog signal to the upconverter <NUM>.

The upconverter <NUM> may output a signal generated by performing frequency up-conversion on the received analog signal to the splitter <NUM>.

In the example shown in <FIG>, the splitter <NUM>, the plurality of blocks <NUM>-<NUM> to <NUM>-n, and the plurality of PAs <NUM>-<NUM> to <NUM>-n may operate as an analog beamformer. An analog beamformer may perform analog beamforming on an input signal.

According to an embodiment, the splitter <NUM> may split an input signal into a plurality of signals and output the split signals respectively to the blocks <NUM>-<NUM> to <NUM>-n. Each of the blocks <NUM>-<NUM> to <NUM>-n may include a phase shifter and an attenuator but is not limited thereto. Each of the blocks <NUM>-<NUM> to <NUM>-n may change the phase and/or amplitude of an input signal. Output signals of the blocks <NUM>-<NUM> to <NUM>-n may be input respectively to the PAs <NUM>-<NUM> to <NUM>-n. Each of the PAs <NUM>-<NUM> to <NUM>-n may amplify and output an input signal, and output signals of the PAs <NUM>-<NUM> to <NUM>-n may be transmitted respectively to the antennas <NUM>-<NUM> to <NUM>-n.

Signals output from the antennas <NUM>-<NUM> to <NUM>-n may be received by the antenna <NUM> of the observation receiver <NUM>. In the example shown in <FIG>, the antenna <NUM> of the observation receiver <NUM> may be located in a far field of the antennas <NUM>-<NUM> to <NUM>-n.

The signals received by the antenna <NUM> of the observation receiver <NUM> may be input to the downconverter <NUM>, and the downconverter <NUM> may perform frequency down-conversion on input signals. Output signals of the downconverter <NUM> may be input to the ADC <NUM>.

The ADC <NUM> may convert input signals into digital signals. According to an embodiment, the sampling time of the ADC <NUM> may be less than "<NUM>/signal bandwidth", and the sampling frequency of the ADC <NUM> may be less than "twice the signal bandwidth". Accordingly, the ADC <NUM> may perform high-speed processing.

Output signals of the ADC <NUM> may be input to the processor <NUM>. The processor <NUM> may determine a DPD parameter based on the output signals of the ADC <NUM> and the captured input signal and control the DPD unit <NUM> based on the determined DPD parameter. According to an embodiment, the processor <NUM> may calculate a coefficient of a DPD function (e.g., the first DPD function or the second DPD function) of the DPD unit <NUM> using the output signals of the ADC <NUM> and the captured input signal of the DPD unit <NUM> and transmit the calculated coefficient to the DPD unit <NUM>. The DPD unit <NUM> may update the existing coefficient of the DPD function with the received coefficient and distort the input signal through the DPD function with the coefficient updated.

<FIG> is a diagram illustrating another example of a transmitter and an observation receiver in a communication device according to various embodiments.

Referring to <FIG>, a communication device <NUM> may include a processor <NUM>, a transmitter <NUM>, and an observation receiver <NUM>. Although not shown in <FIG>, the communication device <NUM> may include a receiver <NUM>. The transmitter <NUM> and the observation receiver <NUM> to be described with reference to <FIG> may correspond to an example of the transmitter <NUM> and an example of the observation receiver <NUM> of <FIG>, respectively.

In the example shown in <FIG>, the transmitter <NUM> may include a DPD unit <NUM>, a first conversion unit <NUM>, an upconverter <NUM>, a splitter <NUM>, a plurality of blocks <NUM>-<NUM> to <NUM>-n, a plurality of PAs <NUM>-<NUM> to <NUM>-n, and a plurality of antennas <NUM>-<NUM> to <NUM>-n. The observation receiver <NUM> may include an antenna <NUM>, a downconverter <NUM>, and an ADC <NUM>.

Since the transmitter <NUM> of <FIG> may be substantially the same as the transmitter <NUM> described with reference to <FIG>, a detailed description of the transmitter <NUM> of <FIG> will be omitted.

Signals output from the antennas <NUM>-<NUM> to <NUM>-n may be received by the antenna <NUM> of the observation receiver <NUM>. In the example shown in <FIG>, the antenna <NUM> of the observation receiver <NUM> may be located in a near field of the antennas <NUM>-<NUM> to <NUM>-n.

The ADC <NUM> may convert the input signals into digital signals. According to an embodiment, the sampling time of the ADC <NUM> may be less than "<NUM>/signal bandwidth", and the sampling frequency of the ADC <NUM> may be less than "twice the signal bandwidth". Accordingly, the ADC <NUM> may perform high-speed processing.

Since the processor <NUM> of <FIG> may operate substantially the same as the processor <NUM> of <FIG>, a detailed description of the processor <NUM> of <FIG> will be omitted.

<FIG> is a diagram illustrating still another example of a transmitter and an observation receiver in a communication device according to various embodiments.

In the example shown in <FIG>, the transmitter <NUM> may include a DPD unit <NUM>, a first conversion unit <NUM>, an upconverter <NUM>, a splitter <NUM>, a plurality of blocks <NUM>-<NUM> to <NUM>-n, a plurality of PAs <NUM>-<NUM> to <NUM>-n, a plurality of couplers <NUM>-<NUM> to <NUM>-n, and a plurality of antennas <NUM>-<NUM> to <NUM>-n. The observation receiver <NUM> may include an anti-beamformer <NUM>, a downconverter <NUM>, and an ADC <NUM>.

The DPD unit <NUM>, the first conversion unit <NUM>, the upconverter <NUM>, the splitter <NUM>, the plurality of blocks <NUM>-<NUM> to <NUM>-n, and the plurality of PAs <NUM>-<NUM> to <NUM>-n of <FIG> may operate substantially the same as the DPD unit <NUM>, the first conversion unit <NUM>, the upconverter <NUM>, the splitter <NUM>, the plurality of blocks <NUM>-<NUM> to <NUM>-n, and the plurality of PAs <NUM>-<NUM> to <NUM>-n of <FIG>. A detailed description of the DPD unit <NUM>, the first conversion unit <NUM>, the upconverter <NUM>, the splitter <NUM>, the plurality of blocks <NUM>-<NUM> to <NUM>-n, and the plurality of PAs <NUM>-<NUM> to <NUM>-n of <FIG> will be omitted.

Output signals of the plurality of PAs <NUM>-<NUM> to <NUM>-n may be input respectively to the couplers <NUM>-<NUM> to <NUM>-n. Each of the couplers <NUM>-<NUM> to <NUM>-n may couple the input signal and transmit the coupled input signal to the anti-beamformer <NUM> of the observation receiver <NUM>.

The anti-beamformer <NUM> may perform anti-beamforming on the signals received respectively from the couplers <NUM>-<NUM> to <NUM>-n and output a signal generated through anti-beamforming to the downconverter <NUM>. The downconverter <NUM> may perform frequency down-conversion on the input signal. An output signal of the downconverter <NUM> may be input to the ADC <NUM>.

The ADC <NUM> may convert the input signal into a digital signal. According to an embodiment, the sampling time of the ADC <NUM> may be less than "<NUM>/signal bandwidth", and the sampling frequency of the ADC <NUM> may be less than "twice the signal bandwidth". Accordingly, the ADC <NUM> may perform high-speed processing.

According to an embodiment, in a first operation (e.g., a DPD parameter update operation), the transmitter <NUM>, <NUM>, <NUM>, or <NUM> may distort an input signal through the DPD unit <NUM>, <NUM>, or <NUM>, convert the distorted input signal into an analog signal, perform frequency up-conversion on the converted analog signal to generate a first signal, amplify the generated first signal, and transmit the amplified first signal to the first receiver <NUM>, <NUM>, <NUM>, or <NUM> through one or more antennas or one or more couplers.

According to an embodiment, in the first operation, the first receiver <NUM>, <NUM>, <NUM>, or <NUM> may perform frequency down-conversion on the received first signal to generate a second signal, convert the second signal into a digital signal through the ADC <NUM>, <NUM>, or <NUM>, and transmit the converted digital signal to the processor <NUM>, <NUM>, <NUM>, or <NUM>, and may be deactivated in a second operation (e.g., a reception operation).

According to an embodiment, in the second operation, the second receiver <NUM> may receive a signal from an external device through one or more antennas.

According to an embodiment, the processor <NUM>, <NUM>, <NUM>, or <NUM> may be coupled with the transmitter <NUM>, <NUM>, <NUM>, or <NUM>, the first receiver <NUM>, <NUM>, <NUM>, or <NUM>, and the second receiver <NUM>.

According to an embodiment, the ADC <NUM>, <NUM>, or <NUM> may be less than the time calculated using the transmission signal bandwidth of the transmitter <NUM>, <NUM>, <NUM>, or <NUM> and a predetermined value (e.g., "<NUM>").

According to an embodiment, the calculated time may represent a result of dividing the predetermined value by the transmission signal bandwidth.

According to an embodiment, the sampling frequency of the ADC <NUM>, <NUM>, or <NUM> may be less than n times the transmission signal bandwidth of the transmitter <NUM>, <NUM>, <NUM>, or <NUM>.

According to an embodiment, n may include "<NUM>".

According to an embodiment, the processor <NUM>, <NUM>, <NUM>, or <NUM> may determine a predistortion parameter (e.g., a DPD parameter) based on the received digital signal and the input signal of the DPD unit <NUM>, <NUM>, or <NUM> and control the DPD unit <NUM>, <NUM>, or <NUM> based on the determined predistortion parameter.

<FIG> is a flowchart illustrating an operating method of a communication device according to various embodiments.

Operations <NUM> to <NUM> to be described with reference to <FIG> may be included in the DPD parameter update operation described above.

Referring to <FIG>, in operation <NUM>, the processor <NUM> of the communication device <NUM> may control one or more of the plurality of ADCs <NUM>-<NUM> to <NUM>-n in the receiver <NUM> to be turned on and the remaining ADCs to be turned off. Further, the processor <NUM> may capture an input signal of the transmitter <NUM>.

In operation <NUM>, the transmitter <NUM> of the communication device <NUM> may distort an input signal through the DPD unit <NUM>, convert the distorted input signal into an analog signal, perform frequency up-conversion on the converted analog signal to generate a first signal, amplify the generated first signal, and couple the amplified first signal.

In operation <NUM>, the receiver <NUM> of the communication device <NUM> may perform frequency down-conversion on the coupled first signal to generate a second signal and convert the generated second signal into a digital signal through the turned-on one or more ADCs. Further, the receiver <NUM> may transmit the converted digital signal to the processor <NUM>.

The processor <NUM> may determine a DPD parameter (e.g., a coefficient of a DPD function) using the captured input signal and the digital signal received from the receiver <NUM> and control the DPD unit <NUM> based on the determined DPD parameter.

The description provided with reference to <FIG> may also apply to the description of <FIG>, and thus, a detailed description thereof will be omitted.

<FIG> is a block diagram illustrating an electronic device in a network environment according to various embodiments.

Referring to <FIG>, the electronic device <NUM> in the network environment <NUM> may communicate with an electronic device <NUM> via a first network <NUM> (e.g., a short-range wireless communication network), or communicate with at least one of an electronic device <NUM> or a server <NUM> via a second network <NUM> (e.g., a long-range wireless communication network). In an embodiment, the electronic device <NUM> may communicate with the electronic device <NUM> via the server <NUM>. In an embodiment, the electronic device <NUM> may include a processor <NUM>, a memory <NUM>, an input module <NUM>, a sound output module <NUM>, a display module <NUM>, an audio module <NUM>, and a sensor module <NUM>, an interface <NUM>, a connecting terminal <NUM>, a haptic module <NUM>, a camera module <NUM>, a power management module <NUM>, a battery <NUM>, a communication module <NUM>, a subscriber identification module (SIM) <NUM>, or an antenna module <NUM>. In an embodiment, at least one of the components (e.g., the connecting terminal <NUM>) may be omitted from the electronic device <NUM>, or one or more other components may be added in the electronic device <NUM>. In an embodiment, some of the components (e.g., the sensor module <NUM>, the camera module <NUM>, or the antenna module <NUM>) may be integrated as a single component (e.g., the display module <NUM>).

According to an embodiment, the electronic device <NUM> may include the communication device <NUM>, the communication device <NUM>, the communication device <NUM>, the communication device <NUM>, or the communication device <NUM>.

The processor <NUM> may execute, for example, software (e.g., a program <NUM>) to control at least one other component (e.g., a hardware or software component) of the electronic device <NUM> connected to the processor <NUM>, and may perform various data processing or computation. According to an embodiment, as at least a part of data processing or computation, the processor <NUM> may store a command or data received from another component (e.g., the sensor module <NUM> or the communication module <NUM>) in a volatile memory <NUM>, process the command or the data stored in the volatile memory <NUM>, and store resulting data in a non-volatile memory <NUM>. According to an embodiment, the processor <NUM> may include a main processor <NUM> (e.g., a central processing unit (CPU) or an application processor (AP)), or an auxiliary processor <NUM> (e.g., a graphics processing unit (GPU), a neural processing unit (NPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with the main processor <NUM>. For example, when the electronic device <NUM> includes the main processor <NUM> and the auxiliary processor <NUM>, the auxiliary processor <NUM> may be adapted to consume less power than the main processor <NUM> or to be specific to a specified function. The auxiliary processor <NUM> may be implemented separately from the main processor <NUM> or as a part of the main processor <NUM>.

The auxiliary processor <NUM> may control at least some of functions or states related to at least one (e.g., the display module <NUM>, the sensor module <NUM>, or the communication module <NUM>) of the components of the electronic device <NUM>, instead of the main processor <NUM> while the main processor <NUM> is in an inactive (e.g., sleep) state or along with the main processor <NUM> while the main processor <NUM> is an active state (e.g., executing an application). According to an embodiment, the auxiliary processor <NUM> (e.g., an ISP or a CP) may be implemented as a portion of another component (e.g., the camera module <NUM> or the communication module <NUM>) that is functionally related to the auxiliary processor <NUM>. According to an embodiment, the auxiliary processor <NUM> (e.g., an NPU) may include a hardware structure specified for artificial intelligence model processing. An artificial intelligence model may be generated through machine learning. Such learning may be performed, for example, by the electronic device <NUM> in which an artificial intelligence model is executed, or via a separate server (e.g., the server <NUM>). Learning algorithms may include, but are not limited to, for example, supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning. An artificial neural network may include, for example, a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted Boltzmann machine (RBM), a deep belief network (DBN), a bidirectional recurrent deep neural network (BRDNN), deep Q-network, or a combination of two or more thereof but is not limited thereto.

According to an embodiment, the processor <NUM> may include the processor <NUM>, the processor <NUM>, the processor <NUM>, the processor <NUM>, or the processor <NUM>.

The program <NUM> may be stored as software in the memory <NUM>, and may include, for example, an operating system (OS) <NUM>, middleware <NUM>, or an application <NUM>.

The sound output module <NUM> may output a sound signal to the outside of the electronic device <NUM>. The receiver may be used to receive an incoming call. According to an embodiment, the receiver may be implemented separately from the speaker or as a part of the speaker.

The display module <NUM> may include, for example, a control circuit for controlling a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, the hologram device, and the projector.

The audio module <NUM> may convert a sound into an electrical signal or vice versa. According to an embodiment, the audio module <NUM> may obtain the sound via the input module <NUM> or output the sound via the sound output module <NUM> or an external electronic device (e.g., the electronic device <NUM> such as a speaker or a headphone) directly or wirelessly connected to the electronic device <NUM>.

The sensor module <NUM> may detect an operational state (e.g., power or temperature) of the electronic device <NUM> or an environmental state (e.g., a state of a user) external to the electronic device <NUM>, and generate an electric signal or data value corresponding to the detected state.

The interface <NUM> may support one or more specified protocols to be used for the electronic device <NUM> to be coupled with the external electronic device (e.g., the electronic device <NUM>) directly (e.g., by wire) or wirelessly. According to an embodiment, the interface <NUM> may include, for example, a high-definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface.

The connecting terminal <NUM> may include a connector via which the electronic device <NUM> may be physically connected to an external electronic device (e.g., the electronic device <NUM>).

The haptic module <NUM> may convert an electrical signal into a mechanical stimulus (e.g., a vibration or a movement) or an electrical stimulus which may be recognized by a user via his or her tactile sensation or kinesthetic sensation.

The camera module <NUM> may capture a still image and moving images.

According to an embodiment, the power management module <NUM> may be implemented as, for example, at least a part of a power management integrated circuit (PMIC).

The communication module <NUM> may include one or more CPs (e.g., modems) that are operable independently of the processor <NUM> (e.g., an AP) and that support a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module <NUM> may include a wireless communication module <NUM> (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module <NUM> (e.g., a local area network (LAN) communication module, or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device <NUM> via the first network <NUM> (e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network <NUM> (e.g., a long-range communication network, such as a legacy cellular network, a <NUM> network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or a wide area network (WAN)). The wireless communication module <NUM> may identify and authenticate the electronic device <NUM> in a communication network, such as the first network <NUM> or the second network <NUM>, using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the SIM <NUM>.

The wireless communication module <NUM> may support a <NUM> network after a <NUM> network, and next-generation communication technology, e.g., new radio (NR) access technology. The wireless communication module <NUM> may support a high-frequency band (e.g., a mmWave band) to achieve, e.g., a high data transmission rate. The wireless communication module <NUM> may support various technologies for securing performance on a high-frequency band, such as, e.g., beamforming, massive multiple-input and multiple-output (massive MIMO), full dimensional MIMO (FD-MIMO), an array antenna, analog beam-forming, or a large scale antenna. According to an embodiment, the wireless communication module <NUM> may support a peak data rate (e.g., <NUM> Gbps or more) for implementing eMBB, loss coverage (e.g., <NUM> dB or less) for implementing mMTC, or U-plane latency (e.g., <NUM> or less for each of downlink (DL) and uplink (UL), or a round trip of <NUM> or less) for implementing URLLC.

According to an embodiment, the wireless communication module <NUM> may include the transmitter <NUM> and the receiver <NUM> of <FIG>. Further, according to an embodiment, the wireless communication module <NUM> may include the transmitters <NUM>, <NUM>, <NUM>, and <NUM>, the observation receivers <NUM>, <NUM>, <NUM>, and <NUM>, and the receiver <NUM>.

According to an embodiment, the antenna module <NUM> may include an antenna including a radiating element including a conductive material or a conductive pattern formed in or on a substrate (e.g., a printed circuit board (PCB)). In such a case, at least one antenna appropriate for a communication scheme used in a communication network, such as the first network <NUM> or the second network <NUM>, may be selected by, for example, the communication module <NUM> from the plurality of antennas. The signal or the power may be transmitted or received between the communication module <NUM> and the external electronic device via the at least one selected antenna. According to an embodiment, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as a part of the antenna module <NUM>.

Each of the external electronic devices <NUM> or <NUM> may be a device of the same type as or a different type from the electronic device <NUM>. According to an embodiment, all or some of operations to be executed by the electronic device <NUM> may be executed at one or more of the external electronic devices <NUM> and <NUM>, and the server <NUM>. For example, if the electronic device <NUM> needs to perform a function or a service automatically, or in response to a request from a user or another device, the electronic device <NUM>, instead of, or in addition to, executing the function or the service, may request one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and may transfer an outcome of the performing to the electronic device <NUM>. In an embodiment, the external electronic device <NUM> may include an Internet-of-things (IoT) device.

The electronic device according to embodiments disclosed herein may be one of various types of electronic devices. According to an embodiment of the disclosure, the electronic device is not limited to those described above.

It should be appreciated that embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment. As used herein, each of such phrases as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C", may include any one of, or all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as "<NUM>st" and "<NUM>nd," or "first" and "second" may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order).

Various embodiments as set forth herein may be implemented as software (e.g., the program <NUM>) including one or more instructions that are stored in a storage medium (e.g., the internal memory <NUM> or the external memory <NUM>) that is readable by a machine (e.g., the electronic device <NUM>). For example, a processor (e.g., the processor <NUM>) of the machine (e.g., the electronic device <NUM>) may invoke at least one of the one or more instructions stored in the storage medium, and execute it. The one or more instructions may include code generated by a compiler or code executable by an interpreter. Here, the term "non-transitory" simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium.

According to an embodiment, a method according to various embodiments disclosed herein may be included and provided in a computer program product. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., PlayStore™), or between two user devices (e.g., smartphones) directly.

Claim 1:
A communication device (<NUM>) comprising:
a transmitter (<NUM>) configured to, in a first operation, distort an input signal through a digital predistortion, DPD, unit (<NUM>), convert the distorted input signal into an analog signal, perform frequency up-conversion on the converted analog signal to generate a first signal, amplify the generated first signal through a power amplifier, PA (<NUM>), and couple the amplified first signal, the DPD unit (<NUM>) comprising a function for distorting the input signal, the function being determined based on an inverse of a model that models a first nonlinear characteristic of the PA (<NUM>);
a receiver (<NUM>) configured to, in the first operation, receive the coupled first signal from the transmitter (<NUM>), perform frequency down-conversion on the coupled first signal to generate a second signal, and convert the generated second signal into a digital signal through one or more analog-to-digital converters, ADCs, that are turned on among a plurality of ADCs (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>-n); and
a processor (<NUM>) configured to, in the first operation, cause one or more of the plurality of ADCs (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>-n) in the receiver (<NUM>) to be turned on and the remaining ADCs to be turned off,
characterized in that when the function is a function determined based on the inverse of a model that models a first nonlinear characteristic of the PA (<NUM>), the number of ADCs to be turned on in the first operation is determined based on a memory order of the model.