Fujitsu Corporation

Takashi Dateki

Hideto Furukawa

Takashi Seyama

Daisuke Ogawa

Tetsuya Yano

Daisuke Jitsukawa

Masahiko Shimizu

Kazuhisa Obuchi

Akira Ito

Tsuyoshi Hasegawa

Koji Matsuyama

Hiroyuki Seki

Jianming Wu

Nobukazu Fudaba

Shunji Miyazaki

Tomohiko Taniguchi

Takeshi Inoue

Takaharu Kobayashi

Liang Zhou

Hirotoshi Shimizu

Mitsuo Kobayashi

Junya Mikami

Takurou Nishikawa

A wireless communication system includes a wireless transmission device and a wireless reception device. The wireless reception device includes: a plurality of reception antennas; and a processor connected to the reception antennas. The processor executes a process including: selecting transmission beam candidates or reception beam candidates based on a reception power of a signal transmitted by using transmission beams of a first array or of a signal received by using reception beams of the first array, the first array setting a delay difference between a plurality of antennas; and determining a beam pattern of a transmission beam and a reception beam based on a reception power of a signal transmitted by using transmission beam candidates formed by a second array or of a signal received by using reception beam candidates formed by the second array, the second array setting a phase difference between a plurality of antennas.

Wireless communication system, wireless communication device, and beam pattern determination method

A transmission method includes: selecting, from a cooperative cluster covered by a plurality of transmission points that transmit signals in cooperation with each other, a transmission point positioned in vicinity of a boundary between the cooperative cluster and another cooperative cluster; generating a first transmission weight that causes the selected transmission point to form a directional beam directed in a direction different from a direction of the another cooperative cluster; generating, by using the first transmission weight generated, a second transmission weight that weights transmission signals, such that signals that are transmitted simultaneously from the transmission points and addressed to a plurality of transmission destinations are separately received; generating, by using the second transmission weight generated, streams to be transmitted from the transmission points, the streams respectively corresponding to antennas; and transmitting the streams generated, from the transmission points.

Transmission method, base station apparatus, and wireless communication system

A transmitter includes: a plurality of transmission antennas; a channel estimator configured to estimate channels between the plurality of transmission antennas and a plurality of receivers; a scheduler configured to schedule a combination of target receivers of transmitting downlink signals on same radio resource among the plurality of receivers; and a transmitter configured to transmit downlink signals intended for the combination scheduled by the scheduler by beam forming from the plurality of transmission antennas on the same radio resource. The scheduler modifies a selecting rule related to the combination of target receivers in accordance with a delay time of an opportunity of transmitting the downlink signal from a timing of estimating the channels.

Transmitter, wireless communication system, and method for processing in transmitter

A transmission control device includes a memory and a processor connected to the memory. The processor executes a process including: selecting a reference transmission point as a starting point of generating a link from among a plurality of transmission points of which each wirelessly transmits a signal; sequentially selecting the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion; and generating a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points.

Transmission control device, radiocommunication system, and calibration method

A method performed by a transmission device and a reception device in a wireless communication system, the method including: executing a process for receiving a reference signal, which is transmitted from each of plural transmit antennas of the transmission device, through a specific receive antenna which is one of at least one receive antenna of the reception device; executing a process for deciding a transmit antenna weight and a receive antenna weight based on the reference signal, the transmit antenna weight and the receive antenna weight being applied in a case where only the specific receive antenna receives a signal which is transmitted by each of the plural transmit antennas based on same transmission data; and executing a process for transmitting first information about the transmit antenna weight and second information about the receive antenna weight to the transmission device.

Method for controlling wireless communication, wireless communication system, reception device, and transmission device

According to one aspect, a base station that is connected to a plurality of transmission and reception points includes a calibrator. The calibrator calculates calibration coefficients to be multiplied on weights in beamforming communication at each of a plurality of transmission and reception points based on the beamforming communication at each of a plurality of transmission and reception points.

Base station, wireless communication system, and calibration method of wireless communication system

A transmission control device includes an acquiring unit that acquires propagation delay time for each propagation path between a plurality of terminal devices and a plurality of transmitter stations; a selector that selects, based on the propagation delay time acquired by the acquiring unit, combinations of terminal devices having similar propagation delay differences from the plurality of the transmitter stations; and a controller that controls transmission timing of the plurality of the transmitter stations that transmit signals to the combinations of the terminal devices selected by the selector.

Transmission control device and transmission control method

In a multi-carrier cellular system, a second synchronization code (a Walsh code or a GCL series code) mapped on a second synchronization channel is used as a signal for specifying in which cell of the base station a mobile station terminal device itself is. A signal transmitted from the base station to the mobile station terminal device is mapped in a radio frame having two-dimensional extension in frequency and time directions. When mapping a certain series number of the second code for specifying a cell or a cell group on the radio frame as the second synchronization channel, phase rotation or circular shift in which one radio frame is one cycle is applied to the second synchronization code. On the receiving side, the head timing of the radio frame is known by knowing the phase rotation angle or the amount of circular shift of the second synchronization code.

Transmitting and receiving devices in cellular system

A wireless communication method used by a wireless communication apparatus is disclosed. The wireless communication method transmits and receives control information divided into a second control information containing information related to the demodulation and decoding of traffic channel and a first control information containing information related to the MIMO separation of the second control information.

Wireless communication system

A radio communication apparatus including: an antenna configured to receive a frame including reference signals and including other signals corresponding to radio resources to which channels are mapped, and a processor configured to acquire degree of usage of the radio resource, to calculate a reception quality of the reference signals, and to adjust the reception quality in accordance with the degree.

Radio communication apparatus, radio communication system and radio communication method

A transmitter time-division-multiplexes, in time domain, to assign at least a part of a second signal stream of a second channel being relatively high error-resilient compared to a first signal stream of a first channel between a boundary of the blocks and the first signal stream of the first channel of a time-division-multiplexing signal.

Method of signal multiplexing and transmitter in radio communication system

A mobile communication system includes one or more base station apparatuses and a plurality of mobile station apparatuses that communicate with the one or more base station apparatuses. A precoding determining unit of the mobile station apparatuses determines applied precoding to be applied to a transmission signal from the base station apparatuses to the corresponding apparatus. A first transmitting unit of the mobile station apparatuses transmits information of the applied precoding to the base station apparatuses. A second transmitting unit of the base station apparatuses applies the same precoding and transmits a transmission signal to a plurality of mobile station apparatuses that specify the same precoding as the applied precoding.

Mobile communication system, base station apparatus, and communication control method

A mobile terminal includes: a memory; and a processor coupled to the memory and configured to: receive two or more of component carriers of different bandwidths, the component carriers being used for wireless communication performed by the mobile terminal, estimate one or more speeds of the mobile terminal based on respective one or more carriers among the two or more of the component carriers, determine whether the estimated one or more speeds satisfy a given condition, and estimate a speed of the mobile terminal according to a result of the determining.

Speed estimation method in a mobile terminal according to a result of determining a given satisfying condition

A radio communication system including a base station and a mobile station, which perform radio communication. The mobile station includes: a receiver which receives a data signal transmitted from the base station; a controller which switches a number of group units and groups the data signal by the switched number of group units, according to one parameter or a combination of a plurality of parameters out of a type of a channel, a type of modulation scheme and encoding rate, an assigned resource amount, or a number of transmitting antennas of the mobile station, when an ACK signal or an NACK signal in response to the data signal is transmitted; and a transmitter which transmits the ACK signal or NACK signal in each group unit of the data signal. The base station includes: a transmitter which transmits the data signal; and a receiver which receives the ACK or NACK signals.

Growing community of inventors

Kawasaki, Japan

Takashi Dateki