Fujitsu Corporation

Mitsubishi Electric Corporation

Nec Corporation

Fujitsu Optical Components Limited

Kabushiki Kaisha Toshiba

Toshiba Memory Corporation

Fujitsu Limited Co., Ltd.

Fujistu Optical Component Limited

Hiroshi Nishimoto

George Ishikawa

Hiroki Ooi

Hiroaki Tomofuji

Motoyoshi Sekiya

Fumihiro Hasegawa

Akinori Taira

Tadashi Okiyama

Akihiro Okazaki

Masatsugu Higashinaka

Takeshi Ishihara

Kazuo Yamane

Masahiro Sugimoto

Satoru Okano

Takashi Tsuda

Yumiko Kawasaki

Shinji Emori

Naoki Kitamura

Kaoru Tsukamoto

Akira Miyauchi

Naoki Kuwata

Tsuyoshi Yoshida

Hiroshi Kubo

Takashi Sugihara

Hiroyasu Sano

Shigeru Uchida

Hironao Hakogi

Minoru Seino

Hiroshi Hamano

Eisuke Haraguchi

Shusaku Umeda

Takefumi Namiki

Hiroki Iura

Tetsuyuki Suzaki

Yusuke Kinoshita

Yuichiro Oyama

Hiroo Kitasagami

Haruo Tamada

Hiroshi Kuwahara

Satoru Mizuta

Naohiro Shinoda

Michikazu Shima

Toshiyuki Kambe

Koji Tomitsuka

Satoshi Mikami

Takatoshi Minami

Akihiko Sugata

Izumi Amemiya

Yasunori Kato

Katsuhiko Hakomori

Takashi Nishitani

Izumi Yokota

Akihiro Toya

Tomoya Yamaoka

Yasunari Arai

Hajime Imai

Akihiko Ichikawa

Manabu Sakai

Akira Kurita

Akinori Ohashi

Hisao Kawashima

Kanako Yamaguchi

Takashi Touge

Kenichiro Kamohara

Kouichi Sawada

Masaaki Hashida

Kazuyoshi Tsuji

Kouichi Takimoto

A wireless relay station to be included in a ladder-type wireless relay network along a moving route of a moving object includes a relay control unit that includes station identification information in the wireless relay network assigned sequentially along the moving route to each of the wireless relay stations included in the wireless relay network and deployed along the moving route, configures and updates, using a first routing table that provides an address of a destination wireless relay station, a second routing table including the address, the station identification information, and an information update time, being associated with one another, of the destination wireless relay station, and provides control to share, among the wireless relay stations included in the wireless relay network, the second routing table configured and updated by each wireless relay station; and a relay communication unit that performs wireless relay communication with other wireless relay stations.

Wireless relay station, wireless relay system, control circuit, storage medium, and wireless relay method

A transmission apparatus that transmits a block signal including a plurality of data symbols, includes: a data-symbol generation unit that generates a data symbol; a symbol arrangement unit that arranges the data symbol and a same-quadrant symbol such that one same-quadrant symbol that becomes a signal point in a same quadrant in a complex plane is inserted per block at a predetermined position in each block signal to generate a block symbol; a CP insertion unit that inserts a Cyclic Prefix into the block symbol; and an interpolation unit that performs interpolation processing on the block symbol on which CP insertion has been performed.

Transmission apparatus that transmits a block signal

A lower base station according to the present invention includes: a CSI acquisition unit that acquires channel information indicating a channel state between the lower base station and one or more mobile terminals; a lower scheduler unit that transmits the channel information to a higher base station, and determines the number of signal streams and a modulation and coding scheme for a destination terminal that is a mobile terminal selected from among the one or more mobile terminals, based on the destination terminal and a data transmission rate for the destination terminal, sent for notification by the higher base station; and an MU-MIMO signal processing unit that performs Multi User-Multiple Input Multiple Output precoding for the mobile terminal.

Lower radio base station, higher radio base station, and radio base station system

A management server includes a processor and a storage that stores correlation information in which a category into which content is classified, location information, and an access frequency are correlated with one another. The processor acquires access information on an access from a wireless terminal to a content server via an access point and a network, a content requested by the wireless terminal, and location information corresponding to the accessed access point, updates the correlation information by rewriting the access frequency corresponding to a category to which the requested content belongs and the acquired location information, according to the access information, specifies a category and location information such that an access frequency related to the category and location information in the updated correlation information satisfies a criterion, and stores a content belonging to the category in a cache area of an access point corresponding to the location information.

Management server, content management method, and content management program for caching content in an access point

A reception device includes: a reception unit receiving transmission signals; a splitting unit splitting received signals into real component and imaginary component; a narrowing unit narrowing down possible signal point candidates of real component of the signal and imaginary component of the signal to signal point candidates based on the real component and the imaginary component of the split received signal; a signal point candidate hypothesizing unit hypothesizing one signal point candidate of real component from the signal point candidates of real component obtained by narrowing-down and hypothesizing one signal point candidate of imaginary component from the signal point candidates of imaginary component obtained by narrowing-down; and a signal estimation value calculating unit estimating real component of the signal based on the one hypothesized real component signal point candidate and estimating imaginary component of the signal based on the one hypothesized imaginary component signal point candidate.

Reception device, reception method, and communication system

A base station serving as a transmission apparatus includes a plurality of transmission antennas capable of forming beams directed to a plurality of terminals, which are reception apparatus, and a precoder configured to perform outer precoding on transmission signals transmitted from the plurality of transmission antennas. The plurality of terminals include at least one first reception apparatus, which are transmission destinations of the transmission signals, and second reception apparatus, which are reception apparatus other than the first reception apparatus. The precoder performs outer precoding on the transmission signals transmitted from the plurality of transmission antennas so that received power in the second reception apparatus among the plurality of reception apparatus is equal to or less than a threshold.

Transmission apparatus, reception apparatus, control station, communication system, and transmission precoding method

A base station apparatus includes a ground station device and a plurality of ground antenna devices coupled to the ground station device via an optical transmission path. The ground station device performs electrical-optical conversion on an analog electrical signal to be transmitted to a mobile station and a reference clock signal to generate optical signals, performs wavelength division multiplexing on the obtained optical signals to generate a multiplexed optical signal, and outputs the multiplexed optical signal to the optical transmission path. Each of the plurality of ground antenna devices demultiplexes the multiplexed optical signal input from the optical transmission path into demultiplexed optical signals, performs optical-electrical conversion on the demultiplexed optical signals to generate electrical signals, up-converts a frequency of the analog electrical signal obtained through the optical-electrical conversion based on the reference clock signal obtained through the optical-electrical conversion to generate an up-converted signal, and transmits the up-converted signal to the mobile station.

Base station apparatus, ground station device, and ground antenna device

A distributed antenna system includes a plurality of antenna groups which includes first antennas and second antennas. The first antennas form beams in a first direction along a mobile station track and transmit identical signals at identical frequencies. The second antennas form beams in a second direction opposite to the first direction and transmit identical signals at identical frequencies. The antenna groups are installed on one side of the mobile station track. A frequency of signals transmitted by the first antennas belonging to the same antenna group is different from a frequency of signals transmitted by the first antennas belonging to another antenna group adjacent thereto, a frequency of signals transmitted by the second antennas belonging to the same antenna group is different from a frequency of signals transmitted by the second antennas belonging to another antenna group adjacent thereto, and the signals from the first antennas and the signals from the second antennas are transmitted using two frequencies in total.

Distributed antenna system

Transmission apparatus, reception apparatus, and communication system

A transmission device to be applied to a communication system configured to carry out multi-user MIMO downlink communication, includes a precoder configured to apply transmission precoding processing, a nonlinear processor configured to carry out successive interference cancellation, a beam forming controller configured to form a plurality of beams and to control a beam radiation direction, and a user ordering processor configured to estimate a positional relationship among the plurality of user terminals from radiation direction information on each of the beams, order users in ascending order of a distance from a specific user, and determine a pairing of a transmission target user and an interference permissible user. The precoder determines two users of the transmission target user and the interference permissible user for each user based on the pairing result, and carries out null steering for users other than the two users, to thereby carry out the transmission precoding processing.

Transmission device, communication system, and precoding computation method

A distributed antenna system includes a plurality of first antenna groups and a plurality of second antenna groups. The first antenna groups include a plurality of first antennas which forms beams in a first direction along a mobile station track and transmits identical signals at identical frequencies. The second antenna groups include a plurality of second antennas which forms beams in a second direction and transmits identical signals at identical frequencies. The first antennas and the second antennas are installed to face each other across the mobile station track. Each of the first antenna groups uses a frequency different from a frequency used in another first antenna group adjacent thereto, each of the second antenna groups uses a frequency different from a frequency used in another second antenna group adjacent thereto, and two frequencies are used by the first antenna groups and the second antenna groups in total.

An optical transmitter that transmits an optical signal includes a dither superimposing circuit configured to generate a dither signal, the dither signal being used to control an operation of the optical transmitter to output the optical signal, and a control circuit configured to control intermittent superimposition of the dither signal onto a target to be controlled.

Optical transmitter and control method for optical transmitter

An optical transmitter has an optical modulator with a Mach-Zehnder interferometer, a pilot signal generator configured to generate a pilot signal to be superimposed on a drive signal for driving the optical modulator or on a substrate bias voltage applied to the optical modulator, and a controller configured to detect a ratio between a pilot component and a direct current component contained in a light output from the optical modulator and control at least one of an amplitude of the drive signal and a level of the substrate bias voltage such that the ratio becomes a constant value.

Optical transmitter and method of controlling optical modulator

A transmitting apparatus according to the present invention includes transmission antennas capable of forming a plurality of beams respectively directed to a plurality of terminals and a precoder unit that performs precoding on signals transmitted from the transmission antennas such that received power in the terminals excluding a desired terminal serving as a transmission destination of a transmission signal and two or more IUI terminals, which are the terminals other than the desired terminal, is equal to or smaller than a threshold.

Wireless communication system and method for forming a plurality of directed beams and precoding to adjust the received power at selected receiving apparatuses

A transmitting apparatus includes transmission antennas capable of forming a plurality of beams respectively directed to a plurality of terminals and a precoder unit that performs precoding on signals transmitted from the transmission antennas such that received power in the terminals excluding a desired terminal serving as a transmission destination of a transmission signal and IUI terminals, which are the terminals other than the desired terminal, is equal to or smaller than a threshold.

Transmitting apparatus, receiving apparatus, control station, communication system, and transmission precoding method

Growing community of inventors

Tokyo, Japan

Hiroshi Nishimoto