Fujitsu Corporation

Fujitsu Semiconductor Limited

Socionext Inc.

Masataka Umeda

Naoto Adachi

Hiroaki Takagi

Takanori Iwamatsu

Hideki Furudate

Yoshiyuki Oota

Hiromu Matsuzawa

A receiver includes a detector to detect an interfered-with carrier from a received and demodulated signal, a fast Fourier transform computation part to perform fast Fourier transform to convert a time domain signal to a frequency domain signal and adjust an output power level of a desired carrier wave contained in the frequency domain signal based upon the detected interfered-with carrier, and a channel estimation part to estimate a channel characteristic based upon a non-interfered-with pilot signal that is not subject to influence of the interfered-with carrier and an interpolation value interpolated based upon the non-interfered-with pilot signal, the non-interfered-with pilot signal being obtained by removing, based upon the interfered-with carrier, an interfered-with pilot signal that is subject to the influence of the interfered-with carrier and an interpolation value interpolated based upon the interfered-with pilot signal.

Receiver and signal processing method

A likelihood weighting circuit includes a weighting part assigning a weight to a first soft-decision likelihood for a subcarrier in a received signal based on a power value of the received signal or a modulation error ratio of the subcarrier, a first variance calculator calculating a variance of the power value, a second variance calculator calculating a variance of the modulation error ratio, a likelihood measurement part measuring a distribution of a second soft-decision likelihood obtained by assigning the weight to the first soft-decision likelihood, a controller computing a first relaxing level of the power value and a second relaxing level of the modulation error ratio based on the respective variances, and a value of the second soft-decision likelihood, a first normalization processor normalizing the power value based on the first relaxing level, and a second normalization processor normalizing the modulation error ratio based on the second relaxing level.

Likelihood weighting circuit

In an electronic apparatus, a soft decision likelihood value is generated and subject to a decoding process supporting a convolutional code; and a data series is interleaved, subjected to an error correction process, and decoded data is generated. A detecting unit, based on information concerning the position of a symbol for which an error has been corrected successfully by the error correction process, estimates whether an error occurs in a symbol for which the error correction process failed and detects the position of a symbol estimated to have an error. A setting unit sets based on the decoded data and information concerning the position of the symbol estimated to have an error, a correction value of the soft decision likelihood value. The electronic device interleaves the order of a correction value series of the soft decision likelihood value and feeds the resulting correction value series back to the decoding process.

Electronic apparatus, receiving apparatus, and error correction method

A receiver includes a transformation part configured to convert a time domain received signal to a frequency domain signal, a known signal extraction part configured to extract a known signal from the frequency domain signal, an estimation part configured to estimate a channel characteristic based upon the extracted known signal, a time direction extraction part configured to extract channel characteristic values of a particular carrier in a time direction from the estimated channel characteristic, a power spectrum acquiring part configured to acquire a power spectrum from the channel characteristic values extracted in the time direction, an error calculation part configured to calculate a carrier frequency error from the power spectrum, and a carrier correction part configured to correct for a carrier frequency of the received signal based upon the carrier frequency error.

Receiver and synchronization correcting method

A receiving device for receiving OFDM signals in which arrangement of pilot signals changes with symbol time, includes: an inverse Fourier transform unit configured to calculate an impulse response by performing an inverse Fourier transform on pilot signals included in a received signal; a first Doppler frequency estimation unit configured to estimate a first Doppler frequency from a phase rotation amount at peak positions between impulse responses of pilot signals of different subcarriers of the impulse responses; a second Doppler frequency estimation unit configured to estimate a second Doppler frequency from a phase rotation amount between impulse responses of pilot signals of the same subcarrier of the impulse responses; and a Doppler frequency selection unit configured to select one of the first and the second Doppler frequency estimated by the first and the second Doppler frequency estimation unit so as to reduce influence of a multipath.

Receiving device and receiving method for determining doppler frequency from pilot signals using OFDM

A data signal correction circuit includes a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal, a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value, and an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval.

Data signal correction circuit, receiver, and data signal correction method

A reception apparatus includes: a Fourier transform unit to output a converted signal; a propagation path estimation unit to calculate propagation-path-estimated-values based on pilot subcarriers; and a propagation path compensation unit, including a filter, to compensate propagation path distortion, the filter includes: first multipliers to multiply the propagation-path-estimated-values of taps other than a center tap by filtering coefficients; a first adder to add outputs of the first multipliers; a first subtractor to calculate an error between an output of the first adder and a propagation-path-estimated-value of the center tap; a filtering coefficient generation unit to generate the filtering coefficients based on the error; a second multiplier to multiply the propagation-path-estimated-value of the center tap by first coefficient; a third multiplier to multiply the output of the first adder by second coefficient; and a second adder to add an output of the second multiplier and an output of the third multiplier.

Receiver apparatus, method for processing received signal and computer program product

A demodulation circuit includes a hard decision process unit and a soft decision process unit. The hard decision process unit is configured to perform a hard decision process using a demodulated signal, and the demodulated signal is a demodulated received signal. The soft decision process unit is configured to determine a range of assignment with respect to a transitioning part in the demodulated signal, calculate a likelihood value of a bit, and perform a soft decision process.

Demodulation circuit, demodulation method and receiving apparatus

A receiving apparatus includes a symbol timing detection unit, a Fourier transform unit, a first symbol timing correction unit, and an interpolation synthesis unit. The symbol timing detection unit is configured to detect a Fourier transform start position from a received transmitting signal of a symbol unit, the Fourier transform unit is configured to perform a Fourier transform using the detected Fourier transform start position. The first symbol timing correction unit is configured to calculate and correct an amount of change between the Fourier transform start position of a reference symbol and the detected Fourier transform start position, and the interpolation synthesis unit is configured to perform an interpolation synthesis of a plurality of delay profiles corresponding to a plurality of symbols including the reference symbol and a symbol in which the amount of change is corrected.

Receiving apparatus and receiving method

A radio communication apparatus, for use as a base station, includes a receiver configured to receive a signal in a predetermined radio frequency band transmitted from a terminal under control of another radio communication apparatus adjacent to the radio communication apparatus and detecting a receiving condition of the signal and a notifying unit configured to notify the receiving condition to an apparatus performing transmission power control of the signal in the predetermined radio frequency band transmitted from the terminal.

Radio communication apparatus and method, controlling apparatus, mobile communication system

A receiving device includes: a receiver that receives frequency multiplex signal; a first Fourier transformation unit that transforms the received frequency multiplex signal to frequency domain signal; a first time-domain waveform generator that generates a first time-domain waveform by performing inverse Fourier transformation of a plurality of pilot signals which are inserted into the frequency multiplex signal; a second time-domain waveform generator that generates a second time-domain waveform having an aliasing period on the basis of the received frequency multiplex signal; a second Fourier transformation unit that synthesizes the first time-domain waveform to the second time-domain waveform and transforms the synthesized time-domain waveform to frequency-domain information; and a propagation-path compensation unit that compensates a propagation-path of the frequency multiplex signal which is output from the first Fourier transformation unit in accordance with information transformed by the second Fourier transformation unit.

Receiving device

Each mobile terminal apparatus measures receiving power or receiving quality of a signal received from a radio communication apparatus. If a plurality of mobile terminal apparatuses in which the receiving power or the receiving quality is lower than or equal to a determined threshold are detected, then a communication control apparatus selects a mobile terminal apparatus made to function as a relay station from the plurality of mobile terminal apparatuses detected on the basis of a result of measuring the receiving power or the receiving quality. The mobile terminal apparatus selected relays communication between the radio communication apparatus and a mobile terminal apparatus which does not function as a relay station.

Communication control apparatus, mobile terminal apparatus, and radio communication method

A data allocation method in a wireless communication system in which data is allocated in both a time axis direction and frequency axis direction, and data is transmitted between a mobile station and base station according to an allocated schedule, the allocation method including: measuring propagation path information between the mobile station and the base station; and modifying an allocation width of a burst in the time axis direction or in the frequency axis direction based on the propagation path information.

Data allocation method in wireless communication system and wireless communication system

A receiver receives a reception signal subjected to orthogonal frequency division multiplexing modulation or orthogonal frequency division multiple access modulation. The receiver has: an array antenna for receiving the reception signal; adaptive equalizers provided in each of the plurality of antennas, and reducing advanced or delayed waves having a delay time to a main wave in the reception signal; a spatial diversity combining portion which multiplies output signals of the adaptive equalizers by a weighting coefficient and adds the multiplied signals; a weight control portion generating the weighting coefficient; and an equalizer setting unit which estimates an arrival angle and a delay time for each path of the reception signal, and based on the estimation, decides an interference wave to be eliminated by the adaptive equalizers among interference waves, and sets in the adaptive equalizers the delay time of the decided interference wave.

Receiver

A radio base station for performing communication through three or more frequency bands based on orthogonal frequency division multiplexing includes a transmission unit configured to transmit a first channel through at least one of the three or more frequency bands and to transmit a second channel having smaller power than the first channel through at least another one of the three or more frequency bands, the first channel and the second channel being transmittable concurrently in time, a reception condition detecting unit configured to detect a reception condition of one or more mobile stations residing within a local cell, and a scheduling unit configured to select one of the first channel and the second channel, a modulation scheme, and a transmission power to be used for at least a downlink to one of the mobile stations based on the detected reception condition.

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Yokohama, Japan

Masataka Umeda