Kabushiki Kaisha Toshiba

Yoshimasa Egashira

Yasuhiko Tanabe

Tsuguhide Aoki

Keiichi Yamaguchi

Daisuke Takeda

Makoto Tanahashi

Ren Sakata

Ichiro Seto

Takehiko Toyoda

Takayuki Kato

Hironori Uchikawa

Kazumi Sato

Toshiyuki Nakanishi

Kohsuke Harada

Noboru Taga

Atsushi Yamaoka

Yoshimasa Kimoto

Tsughide Aoki

An electronic apparatus according to one embodiment, includes: a signal generator generating a first signal and a second signal; a first characteristic circuitry acquiring first and second distorted signals by giving first and second distortion characteristic to the first and second signals; a first time-characteristic circuitry acquiring a third distorted signal by giving a first time-characteristic to the first distorted signal and acquiring a fourth distorted signal by giving a second time-characteristic to the second distorted signal; a second characteristic circuitry acquiring a fifth distorted signal by giving a second distortion characteristic to the third distorted signal, and acquiring a sixth distorted signal by giving the second distortion characteristic to the fourth distorted signal; and a processing circuitry estimating at least one of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distorted signal, and the sixth distorted signal.

Electronic apparatus and signal processing method

A signal processing device capable of performing a process of reducing peak power without interfering with a transmission signal at a high speed is provided. A signal processing device includes a peak-reduced signal generating device and a band pass filter. The peak-reduced signal generating device divides an input signal having an information component into signal streams for every predetermined number of signals, and generates peak-reduced signal with peak canceling signals on the basis of the signal streams. The peak-reduced signal generating device combines the signal streams which the peak-reduced signals on the basis of an order in which the division into the signal streams has been performed. The band pass filter passes a frequency component corresponding to the information component and rejects a frequency component corresponding to the peak canceling signal with respect to a signal based on a signal from the peak-reduced signal generating device.

Signal processing device

In some embodiments, a wireless communication apparatus may include, but is not limited to, a pilot inserter, a segment divider, a phase rotator, and a first adder. The pilot inserter inserts first and second pilot symbols into a symbol stream. The segment divider divides into a plurality of segments a plurality of subcarriers. Each of the subcarriers is allocated with a respective one of the symbols included in the symbol stream into which the first and second pilot symbols have been inserted. The phase rotator performs, for each segment, a phase rotation to all of the symbols, except for a predetermined one of the first and second pilot symbols, included in the symbol stream. The first adder adds together signals corresponding to the subcarriers included in the plurality of segments to which the phase rotation has been performed by the phase rotator to generate a transmission signal.

Wireless communication apparatus, integrated circuit, transmission method, reception method, and communication method

A modulated signal generating device that modulates an input signal and generates a modulated signal. The modulated signal generating device includes a first to p-th amplifier, where p=3 to N, and N represents an integer equal to or greater than three, a first to p-th control unit, a first to p&#x2212;1-th filter, and a combiner. The first amplifier generates a first amplified signal based on a first control signal. The first control unit generates the first control signal based on a first component signal included in the input signal. The first filter eliminates harmonic component included in a first difference signal representing difference between the input signal and the first component signal, and generates a first filtered signal. The combiner combines the first to a p-th amplified signal to generate the modulated signal.

Modulated signal generating device and wireless device

According to an embodiment, the modulated signal generating device modulates an input signal and generates an output signal. The modulated signal generating device includes a plurality of amplifiers, a combiner, a determining unit and a control signal generating unit. The plurality of amplifiers connects in parallel with one another and each configures to drive based on a control signal and to generate amplified signals. The combiner configures to combine the amplified signals and to obtain the output signal having a stepwise waveform. The determining unit configures to determine number of amplifiers to be driven based on a value of the input signal in a period shorter than a period of the input signal. The control signal generating unit configures to select zero or more amplifiers to be driven from among the amplifiers, based on the number of amplifiers determined by the determining unit, the value of the input signal, and a fluctuation in the value of the input signal, and to generate the control signal for driving the selected amplifier.

According to an embodiment, a signal processing apparatus includes a first switch, a second switch, a corrector and a circuit. The first switch selects one signal from a first signal group including a first signal and a first constant envelope signal to obtain a first selected signal. The second switch selects one signal from a second signal group including a second signal and a second constant envelope signal to obtain a second selected signal. The corrector corrects a characteristic of at least one of the first and second selected signals to obtain a first corrected signal and a second corrected signal. The circuit generates an output signal from the first corrected signal and the second corrected signal.

Signal processing apparatus

A distortion compensation device compensates a distortion component generated in a nonlinear circuit having a nonlinear input-output characteristic. The distortion compensation device includes a predistorter and an estimator. The predistorter converts an input signal into an inverse characteristic signal by using a compensation coefficient so that an estimation value of an inverse characteristic to the nonlinear input-output characteristic is given to the input signal. The estimator generates the compensation coefficient based on the input signal, the inverse characteristic signal and an output signal of the nonlinear circuit.

Distortion compensation device

According to one embodiment, a wireless transmission method is disclosed. The method can perform feedback loop processing including subtracting a feedback data signal obtained by multiplying a feedback processing data signal by a gain from an input data signal to generate the feedback processing data signal. The method can perform beam forming processing with respect to the feedback processing data signal and at least one pilot signal for channel estimation to generate a beam-formed signal. In addition, the method can transmit the beam-formed signal by a plurality of antennas. Precoding processing performed on the pilot signal is only beam forming processing.

Wireless transmission method and apparatus

A wireless communication apparatus generates transmission signal including first and second pilot signal sequences allocated to first and second frequencies symmetrically located in relation to a center frequency, and third and fourth pilot signal sequences allocated to third and fourth frequencies symmetrically located in relation to the center frequency, quadrature-modulates the transmission signal, to obtain a quadrature modulation signal, quadrature-demodulates the quadrature modulation signal, to obtain a reception signal, extracts first to fourth pilot signal sequences from the reception signal, estimates a first transfer characteristic concerning first and second frequency by using first and second pilot signal sequences, estimates a second transfer characteristic concerning third and fourth frequencies using third and the fourth pilot signal sequences, generates a third transfer characteristic from which an influence of transmission IQ imbalance is removed by using first and second transfer characteristic, and estimates, from the third transfer characteristic, reception IQ imbalance characteristic.

Wireless communication method and wireless communication apparatus

A wireless communication apparatus receives an quadrature modulated signal, generate a local signal having a frequency different from a center frequency of the quadrature modulated signal, performs quadrature demodulation on the quadrature modulated signal by using the local signal, to obtain an I channel signal and a Q channel signal, performs Fourier transform on the I channel signal and the Q channel signal, to obtain signals in a frequency domain, and calculates a first correction coefficient for correcting phase distortion and amplitude distortion caused by the quadrature demodulation by using pairs of signals among the signals, each of the pairs are located at symmetrical frequency positions with respect to the frequency of the local signal.

Wireless communication apparatus and receiving method

A receiver of an OFDM signal includes a reception unit to receive an OFDM signal formed by a plurality of OFDM symbols respectively including data subcarriers to which data signals are allocated and pilot subcarriers to which cyclically shifted pilot signals are allocated in frequency domain, an estimator to estimate phase errors of the pilot signals to generate first estimated values related to an offset of the OFDM symbol corresponding to each two or more OFDM symbols in the OFDM signal, a weighting adder to perform weighting additions on the first estimated values to obtain one second estimated value related to the offset, a compensator to compensate the offset by using the second estimated value to obtain a compensated OFDM signal, and a decoder to decode the compensated OFDM signal to reproduce the data signals.

Method for receiving OFDM signal, and receiver

An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

OFDM signal transmission method and apparatus

A wireless communication apparatus includes a plurality of antennas, transmits a plurality of known symbol sequences each including a plurality of known symbols by using the antennas, each of the known symbols having subcarrier arrangement on which plural known information of the each of the known symbols are carried on, and inversion/non-inversion of a phase of known information on one of two adjacent subcarriers of the subcarrier arrangement being controlled in accordance with the number of the known symbols and time position of the each of the known symbols, and transmits data symbols by using the antennas after the known symbol sequences are transmitted.

Wireless communication using a plurality of antennas

A receiving method receiving an OFDM signal including a first OFDM symbol having first and second pilot signals allocated to first and second subcarriers positioned symmetric on the frequency axis, and a second OFDM symbol having third and fourth pilot signals allocated to the first and the second subcarriers, a difference between a product of the first pilot signal and a complex conjugate of the fourth pilot signal and a product of the third pilot signal and a complex conjugate of the second pilot signal being non-zero, estimating a first coefficient representing a change components of an amplitude and a phase, and a second coefficient representing an interference component, using first and second received pilot signals corresponding to the first and third pilot signals, estimating from the first and second coefficients IQ imbalance, and compensating the influence of amplitude and phase errors in accordance with the IQ imbalance.

Growing community of inventors

Kawasaki, Japan

Yoshimasa Egashira