Fujitsu Corporation

Nobukazu Fudaba

Kazuo Nagatani

Hiroyoshi Ishikawa

Hajime Hamada

Yuichi Utsunomiya

Tokuro Kubo

Yasuyuki Oishi

Toru Maniwa

Hiroyuki Hayashi

Yasuhito Funyu

Takayoshi Ode

Toshio Kawasaki

Hideharu Shako

Junji Otonari

Norio Tozawa

Shohei Ishikawa

Takashi Dateki

Hideto Furukawa

Dai Kimura

Takeshi Ohba

Daisuke Ogawa

Kotaro Shiizaki

Mitsuharu Hamano

Michiko Anbe

Tohru Sasaki

Yuki Kanno

Koichi Hanada

A base station device includes: an acquisition unit that acquires reception quality of each of a plurality of carriers from a terminal device that performs primary cell connection for transmission and reception of a control channel signal using a carrier whose reception quality is most preferable; a decision unit that decides an amount of increase in transmission power of one of the carriers based on the reception quality acquired by the acquisition unit; a determination unit that estimates whether switching of the primary cell connection occurs in case of increasing the transmission power by the amount of increase and determines whether to increase the transmission power according to the estimation result; and an instruction unit that instructs a transmission unit to increase the transmission power of the carrier by the amount of increase when the determination unit determines to increase the transmission power.

Wireless communication system, base station device and transmission power control method

A base station serving terminals, the base station including: a memory, and a processor coupled to the memory and configured to: select a terminal among the served terminals based on reception powers or reception qualities at the served terminals, when a number of the served terminals exceeds a threshold, determine an amount of change in transmission parameter so that a reception quality at the selected terminal from another base station satisfies a certain condition in case where a handover of the selected terminal to the other base station is performed, the other base station being selected based on the reception powers or the reception qualities, perform the handover of the selected terminal to the other base station, and change the transmission parameter by the determined amount of change.

Base station and handover control method

A base station includes a first determination unit, a calculation unit, and a control unit. The first determination unit determines whether a terminal in connection with the base station is a terminal passing a cell of the base station. The calculation unit calculates handover frequency of the terminal determined as the passing terminal by the first determination unit. The control unit controls transmission power in accordance with the frequency calculated by the calculation unit.

Base station and method for controlling base station

A base station includes an acquiring unit, a deciding unit, and a control unit. The acquiring unit acquires measurement information related to wireless communication quality of a mobile station. The deciding unit decides, by using the measurement information acquired by the acquiring unit and information that is used to control priority of a handover destination cell indicated by a control station, a cell to which the mobile station is handed over. The control unit hands over the mobile station to the cell decided by the deciding unit.

Base station and base station control method

An amplifying device including: a first amplifier configured to generate a first output signal by amplifying an input signal, a second amplifier configured to generate a second output signal by amplifying the first output signal, and a processor configured to perform a first compensation by compensating a distortion for the second amplifier in accordance with the first output signal and the second output signal.

Amplifying device, distortion compensating device, and amplifying method

A wireless station includes: a receiver configured to receive information on a reception quality from a wireless communication apparatus that is connected to the wireless station; and a processor coupled to the receiver and configured to: calculate, based on the reception quality, an index value indicating a difference between a signal-to-interference ratio in the wireless communication apparatus and transmission power of the wireless station, calculate a statistical amount of the index value calculated with regard to each of the plurality of reception qualities, and determine the transmission power in accordance with the statistical amount.

Wireless station and transmission power determination method

A distortion compensation apparatus for performing distortion compensation processing by applying the inverse properties of distortion properties of the power amplifier to a transmission signal to be input to a power amplifier, includes a plurality of distortion compensation coefficient storage units configured to store a plurality of distortion compensation coefficients used for the distortion compensation processing, an offset correction processing unit configured to subject the distortion compensation coefficient stored in each of the plurality of distortion compensation coefficient storage units to offset correction processing, and to generate distortion compensation coefficients in the case that the offset correction processing has not been performed, corresponding to plurality of distortion compensation coefficient storage units, in a pseudo manner and a distortion compensation processing unit configured to subject the transmission signal to the distortion compensation processing based on the distortion compensation coefficients generated in a pseudo manner.

Distortion compensation apparatus and distortion compensation method

A power amplifier apparatus that includes a processor that performs a first distortion compensation processing on an input signal using a distortion compensation coefficient to obtain a first signal and an amplifier that amplifies the first signal. The processor performs a second distortion compensation processing the amplified signal using the distortion compensation coefficient to obtain a second signal and updates the distortion compensation coefficient to enable convergence between the first signal and the second signal.

Power amplifier apparatus, distortion compensation coefficient updating method, and transmission apparatus

A distortion compensation device which reduces a distortion of an amplifier which is added to an output signal of the amplifier, the distortion compensation device including: a plurality of distortion compensation coefficient storage circuits which stores a plurality of distortion compensation coefficients and outputs the distortion compensation coefficients according to an amplitude of an input signal of the amplifier, a distortion compensating processing circuit which adds the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to the input signal of the amplifier, and a distortion compensation coefficient updating circuit which performs weighting processing on the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to reduce the distortion compensation coefficient and which calculates an update value of the distortion compensation coefficient by using the distortion compensation coefficient which is subjected to the weighting processing.

Distortion compensation device and distortion compensating method

A distortion compensation apparatus includes an amplifying unit, a plurality of distortion compensation coefficient storage units, a first address generating unit, a second address generating unit, and a distortion compensating unit. The amplifying unit amplifies an input signal. A plurality of distortion compensation coefficient storage units store the distortion compensation coefficients for compensating for the distortion of the amplifying unit by being associated with two different addresses. The first address generating unit generates a first address based on the current input signal. The second address generating unit generates a second address different from the first address based on the previous input signal. The distortion compensating unit obtains the distortion compensation coefficient corresponding to a combination of the first and second addresses from each of the distortion compensation coefficient storage units and performs a pre-distortion processing for the current input signal to the amplifying unit using the obtained distortion compensation coefficient.

Distortion compensation apparatus, transmitter, and distortion compensation method

A distortion compensation device includes: a frequency-characteristic adding unit configured to add a frequency characteristic to an error signal to generate an added error signal, the error signal being a difference between an input signal input to an amplifier and an output signal output from the amplifier; a distortion-compensation-coefficient updating unit configured to update a distortion compensation coefficient for compensating for a distortion characteristic of the amplifier based on the added error signal; and a distortion compensation unit configured to perform distortion compensation on the input signal using the updated distortion compensation coefficient.

Distortion compensation device, distortion compensation method, and radio transmitter

A distortion compensation device includes a distortion compensator that predistorts an input signal based on delay signals and distortion compensation coefficients corresponding to the respective delay signals obtained by applying different amounts of delay to the input signal, a calculator that calculates an error signal based on the predistorted input signal and an output signal from an amplifier that amplifies the predistorted input signal, a calculator that calculates prospective distortion compensation coefficients for updating the distortion compensation coefficients, based on the error signal, a saturation processor that performs saturation processing for bringing, when the prospective distortion compensation coefficients do not fall into a preset range, the prospective distortion compensation coefficients into the preset range, and a controller that controls the updating of the distortion compensation coefficients based on pieces of coefficient saturation information indicating whether the saturation processing is performed on the prospective distortion compensation coefficients.

Distortion compensation device, transmitter, and distortion compensation method

A predistorter includes a distortion compensating unit which gives, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to a transmission signal which is to be input to the power amplifier; a distortion compensation signal generating unit which generates a distortion compensation signal indicating the reverse characteristic based on transmission data that is sample data of the transmission signal and the delayed transmission data; and a delay amount control unit which controls a delay amount of the transmission data according to an output signal of the power amplifier.

Predistorter and distortion compensation method

A delay amount estimating apparatus includes a delay value search section that searches for a first delay value smaller than a delay setting value at which a given correlation value between an input signal and a feedback signal is provided, and also for a second delay value greater than the delay setting value, the feedback signal coming from a signal processing apparatus that applies signal processing on the input signal, wherein respective correlation values of the first delay value and the second delay value satisfy a given condition; and a delay estimating section that estimates a delay amount of the feedback signal relative to the input signal based on the first delay value and the second delay value.

Delay amount estimating apparatus and signal transmitting apparatus

A transmission apparatus includes an analog digital converter that performs sampling on a demodulated signal obtained by demodulating a part of an output signal, which is produced by amplifying a modulated signal of a baseband signal including a plurality of signals having frequencies separated from each other, at a sampling frequency lower than a frequency of a given intermodulation distortion component and converting the demodulated signal into a digital signal, a detection section that detects an aliasing component of the given intermodulation distortion component produced by the conversion of the analog digital converter, and a distortion compensation section that compensates an input signal to be modulated for the given intermodulation distortion component in accordance with the detected aliasing component.

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Kawasaki, Japan

Nobukazu Fudaba