Abstract: A wireless communication apparatus includes a plurality of antenna elements; a plurality of power amplifiers provided in the plurality of antenna elements; a processor that outputs a transmission signal to the plurality of power amplifiers; and a plurality of feedback paths each of which allows a feedback signal to be fed back from the plurality of power amplifiers to the processor, wherein the processor executes a process for collectively correcting variations in analog characteristics exhibited in the plurality of feedback paths, and a process for updating, by using the transmission signal and the feedback signal that are obtained by being corrected, a distortion compensation coefficient that is used to compensate nonlinear distortion produced in the plurality of power amplifiers.

Abstract: A signal processing device includes: a first subarray that includes power amplifiers and phase shifters and that forms a first beam facing in a first direction; a second subarray that includes power amplifiers and phase shifters and that forms a second beam facing in a second direction; a feedback unit that feeds back at least signals that are output from the power amplifiers included in the first subarray; and a processor that is connected to the first subarray and the second subarray. The processor executes a process including: generating, based on a first feedback signal and a transmission signal output to the first subarray, a cancellation signal corresponding to an interference component applied to the second beam by the first beam; and adding the generated cancellation signal to a transmission signal output to the second subarray.

Abstract: A wireless communication apparatus includes: a processor that performs distortion compensation on a complex number transmission signal by using a distortion compensation coefficient; a power amplifier that amplifies the transmission signal subjected to distortion compensation by the processor; and a feedback path that feeds back a signal output from the power amplifier to supply a real number feedback signal to the processor. The processor executes a process including: estimating a complex number feedback signal by performing linear computation on the complex number transmission signal and the real number feedback signal; and updating the distortion compensation coefficient by using the estimated complex number feedback signal.

Abstract: A signal processing device includes: a first subarray that includes power amplifiers and phase shifters and that forms a first beam facing in a first direction; a second subarray that includes power amplifiers and phase shifters and that forms a second beam facing in a second direction; a feedback unit that feeds back at least signals that are output from the power amplifiers included in the first subarray; and a processor that is connected to the first subarray and the second subarray. The processor executes a process including: generating, based on a first feedback signal and a transmission signal output to the first subarray, a cancellation signal corresponding to an interference component applied to the second beam by the first beam; and adding the generated cancellation signal to a transmission signal output to the second subarray.

Abstract: A wireless communication apparatus includes: a processor that performs distortion compensation on a complex number transmission signal by using a distortion compensation coefficient; a power amplifier that amplifies the transmission signal subjected to distortion compensation by the processor; and a feedback path that feeds back a signal output from the power amplifier to supply a real number feedback signal to the processor. The processor executes a process including: estimating a complex number feedback signal by performing linear computation on the complex number transmission signal and the real number feedback signal; and updating the distortion compensation coefficient by using the estimated complex number feedback signal.

Abstract: A peak suppression circuit includes a memory, and a processor coupled to the memory and the processor configured to suppress a first peak of a transmission signal according to a first sampling signal having a predetermined period, delay the transmission signal where the first peak is suppressed by a predetermined time corresponding to a period shorter than the predetermined period, and suppress a second peak of the delayed transmission signal according to a second sampling signal having the predetermined period.

Abstract: A multiantenna communication device forms a directional beam by adding an antenna weight to respective signals of a plurality of antenna elements. The multiantenna communication device includes: a processor that executes performing distortion compensation on a transmission signal by using a distortion compensation coefficient; a plurality of power amplifiers that are provided corresponding to the antenna elements, and that amplify the transmission signal subjected to the distortion compensation by the processor; a multiplexer that multiplexes signals output from the power amplifiers to feed back; and an analog/digital (A/D) converter that A/D converts a multiplex feedback signal that is obtained by the multiplexer, wherein the processor executes updating the distortion compensation coefficient by using the multiplex feedback signal A/D converted by the A/D converter and the transmission signal.

Abstract: A peak suppression circuit includes a memory, and a processor coupled to the memory and the processor configured to suppress a first peak of a transmission signal according to a first sampling signal having a predetermined period, delay the transmission signal where the first peak is suppressed by a predetermined time corresponding to a period shorter than the predetermined period, and suppress a second peak of the delayed transmission signal according to a second sampling signal having the predetermined period.

Abstract: A distortion compensating device includes: a filter that receives input of a transmitting signal including a plurality of subcarrier signals assigned to respective frequencies and that superimposes filter coefficients on the respective subcarrier signals; a first signal converting unit that converts the subcarrier signals, on which the respective filter coefficients are superimposed, from a frequency domain into a time domain to obtain an input signal; a distortion compensating unit that superimposes a distortion compensation coefficient on the input signal to obtain an output signal; a power amplifier that amplifies and outputs the output signal; and a control unit that generates the filter coefficients according to an arithmetic equation using the subcarrier signals and a feedback signal from the power amplifier, and outputs the filter coefficients to the filter.

Abstract: A multiantenna communication device forms a directional beam by adding an antenna weight to respective signals of a plurality of antenna elements. The multiantenna communication device includes: a processor that executes performing distortion compensation on a transmission signal by using a distortion compensation coefficient; a plurality of power amplifiers that are provided corresponding to the antenna elements, and that amplify the transmission signal subjected to the distortion compensation by the processor; a multiplexer that multiplexes signals output from the power amplifiers to feed back; and an analog/digital (A/D) converter that A/D converts a multiplex feedback signal that is obtained by the multiplexer, wherein the processor executes updating the distortion compensation coefficient by using the multiplex feedback signal A/D converted by the A/D converter and the transmission signal.

Abstract: A distortion compensating device includes: a filter that receives input of a transmitting signal including a plurality of subcarrier signals assigned to respective frequencies and that superimposes filter coefficients on the respective subcarrier signals; a first signal converting unit that converts the subcarrier signals, on which the respective filter coefficients are superimposed, from a frequency domain into a time domain to obtain an input signal; a distortion compensating unit that superimposes a distortion compensation coefficient on the input signal to obtain an output signal; a power amplifier that amplifies and outputs the output signal; and a control unit that generates the filter coefficients according to an arithmetic equation using the subcarrier signals and a feedback signal from the power amplifier, and outputs the filter coefficients to the filter.

Abstract: There is provided a communication device including a first transmitter configured to up-convert a frequency of a first transmission signal to a first frequency so as to be wirelessly transmitted, a second transmitter configured to up-convert a frequency of a second transmission signal to a second frequency different from the first frequency so as to be wirelessly transmitted, a receiver configured to receive a reception signal including a passive intermodulation signal generated due to the first and second transmission signals wirelessly transmitted, a memory, and a processor coupled to the memory and configured to estimate frequency errors of the up-converted first and second transmission signals, generate a cancellation signal into which any frequency of the first and second transmission signals has been corrected, based on the estimated frequency errors, and combine the cancellation signal with a down-converted reception signal.

Abstract: There is provided a distortion compensation apparatus for compensating a distortion of a power amplifier configured to amplify a transmission signal, the distortion compensation apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire an average power of the transmission signal including a plurality of signal blocks by a signal block of the plurality of signal blocks, calculate a step coefficient value based on the acquired average power, and update a distortion compensation coefficient for compensating the distortion, based on an updating amount according to the calculated step coefficient value.

Abstract: A communication device includes a transmitter to transmit a radio transmission signal having a frequency different from a frequency of a radio transmission signal transmitted by another transmitter, a receiver to receive a receiving signal including a primary signal and a first passive intermodulation signal generated by radio transmission signals, a memory, and a processor coupled to the memory and the processor to calculate a power of the primary signal, update a first coefficient for generating a cancel signal for canceling the first passive intermodulation signal, based on the receiving signal and transmission signals to be transmitted, generate the cancel signal based on the transmission signals and the first coefficient, and combine the receiving signal and the cancel signal, wherein the processor is further to adjust a step coefficient, which is a time constant in case of updating the first coefficient, based on the power of the calculated primary signal.

Abstract: A distortion compensation device includes a distortion compensation unit, a feedback coefficient calculating unit, a clip processing unit, and an updating unit. The distortion compensation unit generates a distortion compensation signal from a transmission signal by using a distortion compensation coefficient and inputs the generated distortion compensation signal to a power amplifier. The feedback coefficient calculating unit calculates a feedback coefficient based on an output signal from the power amplifier. The clip processing unit outputs the feedback coefficient when absolute value of the feedback coefficient is less than a threshold. Furthermore, the clip processing unit outputs a feedback coefficient of which absolute value is less than the threshold when the absolute value of the feedback coefficient is greater than the threshold.

Abstract: A distortion compensation device includes a first table, a second table, a calculating unit, a first updating unit, and a second updating unit. The first table holds a coefficient of a nonlinear term included in a filtering coefficient associated with an address other than a prescribed address obtained from the input signal x(n). The second table holds a coefficient of a linear term related to the prescribed address. The calculating unit calculates, based on the output signal, each of the update amounts of the coefficient of the nonlinear term and the coefficient of the linear term. The first updating unit updates each of the coefficients in the first table based on the update amount of the coefficient of the nonlinear term. The second updating unit updates each of the coefficients of the second table based on the update amount of the coefficient of the linear term.

Abstract: A distortion compensation apparatus includes a retention unit that retains a coefficient for distortion compensation for each of a plurality of time segments of a burst signal that keeps a constant power level, and a distortion compensation unit that, by using a coefficient for a time segment that corresponds to elapsed time from a head of the burst signal among the coefficients retained by the retention unit, executes distortion compensation for the time segment.

Abstract: A distortion compensation device includes: a storage configured to store a distortion compensation coefficient for compensating a distortion of a transmission signal to be amplified and transmitted, by corresponding to a combination of a plurality of addresses; a first generator configured to generate a first address according to a power or an amplitude of an input signal; a second generator configured to generate a second address according to a first vector to interconnect sample points on an IQ plane where the sample points of the input signal are drawn in time series; and a distortion compensation unit configured to acquire the distortion compensation coefficient corresponding to a combination of the first address and the second address from the storage, and to perform a predistortion processing on the input signal, by using the acquired distortion compensation coefficient, so as to generate the transmission signal.

Abstract: A radio communication device includes: an instantaneous coefficient acquisition unit that acquires an instantaneous coefficient that corrects an instantaneous change contained in a burst distortion corresponding to an elapsed time from a top of a burst signal in which a constant power level continues and instantaneously changes the power level of the burst signal; an average coefficient acquisition unit that acquires an average coefficient that corrects an average change contained in the burst distortion and gradually changes the power level of the burst signal from the top to an end of the burst signal; a synthesizer that synthesizes the instantaneous coefficient acquired by the instantaneous coefficient acquisition unit with the average coefficient acquired by the average coefficient acquisition unit; and a corrector that uses a correction coefficient obtained from the synthesizing by the synthesizer to correct the burst distortion occurring in the burst signal.