Fujitsu Corporation

Fujitsu Connected Technologies Limited

Daisuke Jitsukawa

Hiroyuki Seki

Kenji Suda

Yoshinori Tanaka

Kotaro Shiizaki

Yoshihiro Kawasaki

Takashi Dateki

Jianming Wu

Takato Ezaki

Tetsuya Yano

Yoshiaki Ohta

Takashi Seyama

Michiharu Nakamura

Masafumi Tsutsui

Hongyang Chen

Kazuto Sato

Shin Hosokawa

Shunsuke Iizuka

A communication apparatus that communicates with a terminal device using a multi-input multi-output (MIMO) data transfer method includes: a memory; and a processor coupled to the memory and configured to: estimate a reception signal to interference ratio (SIR) of a wireless propagation path between the communication apparatus and the terminal device; acquire an SIR offset value for a transmission rank based on a state of occurrence of transfer errors; and switch the transmission rank based on the reception SIR and an SIR offset value for the transmission rank.

Communication apparatus, wireless communication system, and transmission rank switching method

A mobile station configured to perform radio communication using spatial multiplexing with a base station, the mobile station including: a controller configured to select a data unit with highest channel quality, and to select a spatial layer with highest reception quality belonging to the selected data unit; and a transmitter configured to transmit spatial coding information and first identification information to the base station, the spatial coding information corresponding to the number of spatial layers, and the first identification information identifying the spatial layer selected, and a layer indicator to determine a precoding matrix.

Mobile station, base station, and communication control 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 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 wireless communications system includes: a base station configured to switch a first state of storing to a predetermined region of control information transmitted to a terminal, a value instructing a transmission power of the terminal, and a second state of storing to the predetermined region of the control information, a value instructing number of repetitions of transmission of a same data by the terminal; and the terminal configured to switch a third state of controlling the transmission power based on the value stored to the control information received from the base station in the first state, and a fourth state of controlling the number of repetitions of transmission of the same data with a maximum transmission power by the terminal, based on the value stored to the control information received from the base station in the second state.

Wireless communications system, base station, terminal, and process method

A transmission control device includes a memory; and a processor connected to the memory and configured to: specify layers corresponding to a number of hops of a link generated between a plurality of transmission points each of which wirelessly transmits a signal; and allocate radio resources which are used for transmission and reception of the signal and consecutive on a time axis to transmission points belonging to adjacent layers while sequentially switching the specified layers.

Transmission control device, radio communication system, and radio resource allocation 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 mobile station is configured to perform radio communication using spatial multiplexing with a base station. The mobile station includes a selecting unit and a transmitting unit. The selecting unit selects a data unit with highest channel quality from a plurality of data units and selects a spatial layer with highest reception quality from spatial layers belonging to the data unit. The transmitting unit transmits identification information of the spatial layer selected by the selecting unit to the base station as control information.

A wireless communications system includes a base station configured to switch a first state of storing to control information transmitted to a terminal, a value instructing a transmission power of the terminal, and a second state of storing to the control information, a value instructing a transmission count of multiple transmissions of a same data by the terminal; and the terminal configured to switch a third state of adjusting the transmission power based on the value stored to the control information received from the base station in the first state, and a fourth state of adjusting the transmission count of multiple transmissions of the same data by the terminal, based on the value stored to the control information received from the base station in the second state.

A base station includes a scheduler which allocates a first radio resource and a second radio resource while the first radio resource is used to transmit a control channel signal from a wireless terminal, and the second radio resource is used to transmit from the wireless terminal a first reference signal corresponding to the control channel signal even when the wireless terminal does not transmit the control channel signal by using the first radio resource.

Base station, wireless terminal and wireless communication system

A transmission device including: a memory, and a processor coupled to the memory and configured to, when data is transmitted to a reception device, transmit a first signal that includes the data and a second signal generated by performing, based on identification information of the reception device, phase modulation on a known signal.

Transmission device, reception device, transmission method, and reception method

A communication apparatus includes a memory, and a processor coupled to the memory and configured to receive a first reception signal and a second reception signal in a first period, calculate a first phase rotation quantity between the first reception signal and the second reception signal, receive a third reception signal and a fourth reception signal in a second period, calculate a second phase rotation quantity between the third reception signal and the fourth reception signal, determine whether to compensate for a frequency offset of a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity, and when it is determined to compensate for the frequency offset of the fifth reception signal, compensate for the frequency offset of the fifth reception signal.

Communication apparatus, communication method and communication system

A base station apparatus includes a processor. The processor executes a process including obtaining information indicating a radio status of each mobile station apparatus relevant to first communication in which radio communication is performed between the mobile station apparatuses via the base station apparatus, and second communication in which radio communication is directly performed between the mobile station apparatuses without via the base station apparatus; and notifying, based on the obtained information, the mobile station apparatuses that perform the second communication of control information for controlling the second communication.

Base station apparatus, mobile station apparatus, radio communication system, communication control method of base station apparatus, and communication control method of mobile station apparatus

A wireless communication method including: when transmitting data from at least one of a plurality of transmission apparatuses to a reception apparatus using a radio resource, selecting a first transmission scheme or a second transmission scheme based on a status of transmission from the plurality of transmission apparatuses, the first transmission scheme in which the plurality of transmission apparatuses transmit same data to same reception apparatus using same radio resource, the second transmission scheme in which one transmission apparatus of the plurality of transmission apparatuses transmits the data to the reception apparatus using the radio resource.

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Adachi, Japan

Daisuke Jitsukawa