Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Tohoku University

Akinori Fujimura

Toshiharu Kojima

Seiji Okubo

Yasushi Sogabe

Hitomi Ono

Futaba Ejima

Yuichi Yamamoto

Shigenori Tani

Katsuyuki Motoyoshi

Tsuyoshi Sasaki

Yuta Takemoto

Terumi Sunaga

Masaaki Kusano

Yukimasa Nagai

Tadashi Takagi

Fumio Ishizu

Hiroyasu Sano

Makoto Miyake

Yoshio Inasawa

Takashi Kuwahara

Takashi Asahara

Makoto Yamazaki

Kazunari Kihira

Hiroaki Hirai

Shinya Hirakuri

Toshiyuki Kuze

Kazuo Tsubouchi

Minoru Akita

Hiroyuki Nakase

Suguru Kameda

Yosikatu Tajima

Tomohiro Ogino

Mari Otiai

Toshiyasu Tsunoda

Kazuyoshi Tsuji

Kyoichiro Izumi

Keishi Takeda

Shoichi Oshima

A satellite receiver includes: demultiplexing units each demultiplexing, into subchannel signals of a predetermined band, a digital reception signal obtained by converting a calibration signal received by a corresponding one of receiving antenna elements into a digital signal; excitation coefficient multiplication units multiplying the subchannel signals by an excitation coefficient; a complex adder adding the subchannel signals multiplied by the excitation coefficient together for each subchannel signal of the same band; a correlation detection unit calculating, with the use of one demultiplexing unit as a reference demultiplexing unit, a cross-correlation value for each subchannel signal output from each demultiplexing unit different from the reference demultiplexing unit with respect to a subchannel signal of a same band output from the reference demultiplexing unit; and an excitation coefficient generation unit generating a corrected excitation coefficient based on a cross-correlation value and an excitation coefficient created in advance.

Satellite receiver and satellite communication system

A satellite transmitter includes K transmission antenna elements, a multiplexing unit configured to multiplex each of K digital signals on a frequency axis and then convert the multiplexed digital signals to time-domain digital signals, a digital-to-analog converter, a PAPR calculation unit configured to calculate a PAPR for each of the K digital signals, a beam-to-beam relative phase calculation unit configured to calculate a beam-to-beam relative phase for suppressing a peak power of the transmission antenna elements, an excitation coefficient calculation unit configured to calculate K updated excitation coefficients based on the beam-to-beam relative phase and the beam-formation excitation coefficient, and an excitation coefficient multiplication unit configured to generate the digital signals of a frequency domain to be output to the multiplexing unit by multiplying a received relay signal by each of the K updated excitation coefficients in the frequency domain.

Satellite transmitter and relay satellite communication system

Provided is a digital switch including: a plurality of input-side memories, which are arranged in a one-to-one correspondence with a plurality of input ports, and are configured to accumulate time-division multiplexed data; a plurality of output-side memories, which are arranged in a one-to-one correspondence with a plurality of output ports, and are configured to accumulate time-division multiplexed data; and a switch matrix configured to receive, as input, the time-division multiplexed data read out in every cycle from each of the plurality of input-side memories, and execute routing for selecting, in accordance with a connection control signal received from outside, any one of the plurality of output-side memories such that the time-division multiplexed data read out in every cycle is output from each of the plurality of output ports without causing a difference in delay, to output the time-division multiplexed data.

Digital switch, wireless communication device, control station, and wireless communication control method for switching a route of communication data

A multi-stage demultiplexing circuit in which a plurality of circuits each combining a selector and a frequency decimation circuit are connected is included. The selector selects one of input signals based on a control signal, and generates a plurality of output signals. The plurality of output signals output from the selector are input to the frequency decimation circuit, and the frequency decimation circuit performs frequency conversion processing, low pass filter processing, and down-sampling processing based on a control signal to generate an output signal. Two or more reception signals are input to the multi-stage demultiplexing circuit, and the multi-stage demultiplexing circuit executes demultiplexing processing based on a control signal so that an output signal that includes an unused band portion is prevented from being output downstream.

Demultiplexing circuit, multiplexing circuit, and channelizer relay unit

A satellite receiver includes: N reception antenna elements; N demultiplexing units; a correlation detection unit configured to perform correlation processing on each of reception signals demultiplexed by the N demultiplexing units with a reception antenna element that receives the highest power being set as a reference element so as to calculate a relative phase difference, and calculate an excitation coefficient for cancelling a phase difference between the N reception antenna elements for each of sub-channels based on the calculated relative phase difference; N phase compensation units configured to multiply the reception signals demultiplexed by the N demultiplexing units, respectively, by the excitation coefficient for each of the sub-channels; and a combiner configured to combine multiplication results from the N phase compensation units for each of the sub-channels to generate output signals.

Provided is a communication system including a control station and a satellite repeater capable of forming two or more beams. The control station includes a control unit that classifies the two or more beams into clusters each made up of two or more beams among the two or more beams and allocates different frequencies to the beams belonging to one of the clusters. The satellite repeater includes a channelizer that performs exchanging processing on an input reception signal and outputs the reception signal having undergone the exchanging processing, as a transmission signal. A signal used in the exchanging processing includes a signal obtained by combining signals corresponding to the beams defining the one cluster.

Communication system, repeater, control station, and control method

A transmitting station includes a transmitting antenna whose orientation direction is changeable, and a controller that controls the orientation direction of the transmitting antenna according to an orientation direction of the transmitting antenna determined together with receiving stations to receive data transmitted from the transmitting antenna based on estimate values of received signal quality at receiving stations that are candidates for receiving stations to receive data transmitted from the transmitting antenna. The transmitting station can maintain received signal quality at a plurality of receiving stations at a desired value or more in a data transmission system.

Transmitting station, control station, receiving station, data transmission system, and data transmission method

A relay side receiving unit () receives a relay signal (), an analog relay unit () outputs by analog processing the relay signal () whose frequency bandwidth is controlled, and a digital relay unit () outputs by digital processing the relay signal () whose frequency bandwidth is controlled. A relay side transmitting unit () transmits the relay signal () output by the analog relay unit (), the digital relay unit (). A relay side control unit () controls the analog relay unit (), the digital relay unit () in accordance with an analog relay unit control signal (A), a digital relay unit control signal (D) indicating a frequency band of the relay signal ().

Multi-beam satellite communication system

A receiver includes a reception antenna, a reception unit, and a demodulation unit. The reception unit sequentially receives modulated signals resulting from spread spectrum via the reception antenna. The demodulation unit demodulate a first signal received by the reception unit by performing despreading using a short-period spreading code, the first signal including information for identifying a long-period spreading code. The demodulation unit identifies the long-period spreading code on the basis of the information obtained from the first signal. The demodulation unit then demodulates a second signal received by the reception unit after the first signal by performing despreading using the long-period spreading code.

Receiver, transmitter, radio communication system, and radio communication method

A demodulation apparatus demodulates spectrum-spread received data, and includes a band variable filter removing noise components from despread received data, a power conversion unit converting each sample value of received data after removing noise components to a power value, a cyclic addition unit cyclically adding the power value in bit periods of received data, a maximum-value detection/average-level measurement unit detecting a maximum value from a cyclic-addition result of the cyclic addition unit, an estimation unit estimating a spreading-code timing and a carrier frequency based on maximum-value information detected by the maximum-value detection/average-level measurement unit, a spreading-code generation unit generating a spreading code with a timing according to an estimation result of a spreading-code timing obtained by the estimation unit, and a local-signal generation unit setting a local-signal frequency according to an estimation result of a carrier frequency obtained by the estimation unit.

Demodulation apparatus

A relay apparatus includes a reception analog filter that extracts a desired signal from a received signal, an A/D converter that converts the signal after passage through the reception analog filter into a digital signal, a demultiplexing unit that demultiplexes the digital signal converted by the A/D converter into m signals, a reception-side compensating unit that digitally compensates for an analog characteristic of the reception analog filter with respect to the m signals demultiplexed by the demultiplexing unit, and a multiplexing unit that multiplexes the m signals digitally compensated by the reception-side compensating unit. The reception-side compensating unit further demultiplexes each of x signals not sufficiently compensated among the digitally-compensated m signals into k signals, digitally compensates for the analog characteristic of the reception analog filter, and multiplexes the k signals after the digital compensation.

Demultiplexing apparatus, multiplexing apparatus, and relay apparatus

A demultiplexing apparatus includes a signal receiving unit that receives signals, an analog demultiplexing unit that analog-demultiplexes, in predetermined units of channels, received signals received by the signal receiving unit and generates analog demultiplexed signals, and a plurality of digital demultiplexing units that digital-demultiplex the analog demultiplexed signals in units of sub-channels and generate digital demultiplexed signals. The analog demultiplexing unit controls, concerning the analog demultiplexed signals output to the digital demultiplexing units, a total value of bandwidths in which a signal is present so as to be a predetermined value or less.

A wireless communication apparatus reducing power consumption of a large circuit size switch unit, includes a demultiplexing unit that separates an input multiplexed signal into plural signals for each input port, a prestage rearrangement unit that rearranges the plural signals input from the demultiplexing unit and outputs plural prestage rearranged signals for each input port, a switch unit that inputs the plural prestage rearranged signals output from the prestage rearrangement unit provided for each input port as plural signals before switching and applies switching processes to the plural signals before the switching to be output as plural switched signals for each output port, a poststage rearrangement unit that inputs and rearranges the plural switched signals output from the switch unit for each output port and outputs plural poststage rearranged signals for each output port, and a multiplexing unit that multiplexes the plural poststage rearranged signals for each output port.

Wireless communication apparatus and wireless communication control method that performs communication using a frequency division multiplexing method

A reply apparatus includes: a reception analog switch matrix that outputs, to reception processing units, a wideband reception signal in a band wider than the bandwidth processable by the reception processing unit; a connecting unit that outputs demultiplexed signals to transmission processing units; a transmission analog switch matrix that outputs, to the same transmission antennas, signals subjected to transmission processing; a local generating unit that generates and transmits local signals having different frequencies to the reception processing units; a local-phase-difference calculating unit that calculates a phase difference between the local signals and inputs the phase difference to the reception processing units; and reception-phase correcting units that perform phase correction on the basis of the phase difference. The reception processing units, when the wideband reception signal is input, apply reception processing to divided signals obtained by extracting a part of bands of input signals on the basis of the local signals.

Relay apparatus, relay satellite, and satellite communication system

A demultiplexing apparatus includes: a demultiplexed-signal selecting and distributing unit configured to apply frequency conversion processing and down-sampling processing to one or more reception signals and output reception signals to a designated output destination; frequency converting and reception low-pass filter units configured to apply frequency conversion processing and low-pass filter processing to reception signals and output reception signals while down-sampling reception signals; selector units configured to switch an input source of a signal output to the frequency converting and reception low-pass filter unit at a next stage; reception-channel filter units configured to subject signals from the frequency converting and reception low-pass filter units to waveform shaping with a desired frequency characteristic and output the signals; and a filter-bank control unit configured to generate, based on channel information estimated from one or more reception signals, a control signal controlling the demultiplexed-signal selecting and distributing unit and the selector units.

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Tokyo, Japan

Akinori Fujimura