Fujitsu Corporation

Kaoru Yokoo

Yasuyuki Oishi

Yoji Ohashi

Yuuta Nakaya

Tatsuya Kikuzuki

Takeshi Toda

Atsushi Honda

Mitsuhiro Azuma

Hiromasa Yamauchi

Kazuo Nagatani

Manabu Kai

Kazuyuki Ozaki

Teruhisa Ninomiya

Hiroshi Fujita

Masafumi Katoh

Kensuke Sawada

Takayuki Sasaki

Ichirou Ida

Kazumi Kasai

Makoto Hamaminato

Takahiro Suzuki

Satoshi Mikami

Akihiro Wada

Kenichi Nishikawa

Shinsuke Hara

Hiroo Urabe

Yuji Irie

An information processing apparatus includes a memory, and a processor coupled to the memory and configured to obtain location information indicating locations of a wireless transmitter and a wireless receiver, simulate a first power of a first reception signal at the wireless receiver in a condition that a radio signal is transmitted from the wireless transmitter, identify a first probability distribution model in accordance with the first reception signal, identify a first parameter of the first probability distribution model in accordance with the first power and a propagation environment defined by the locations of the wireless transmitter and the wireless receiver indicated by the location information, and based on the first probability distribution model using the first parameter, simulate a second power of a second reception signal at around the wireless receiver.

Information processing apparatus, method and non-transitory computer-readable storage medium

A wireless communication apparatus includes antenna elements, each receiving a first signal and a second signal, a first estimator that estimates first channel information of the first signal, a false signal generator that generates false signals that are equal in number to or greater in number than the number of the antenna elements, each of the false signals arriving from a unique direction that is different from a direction of arrival of the first signal, a weight generator that generates first weights, each being associated with a corresponding one of the false signals and forming a null in the direction of arrival of the first signal, a multiplier that multiplies a signals received by the respective antenna elements by the first weights to acquire weight-multiplied signals, and a second estimator that estimates second channel information of the second signal using the weight-multiplied signals.

Wireless communication apparatus, wireless communication system, and channel estimating method

A radio communication device includes: a receiver configured to receive a radio signal; and a processor coupled to the receiver, configured to switch between a first communication mode and a second communication mode in accordance with scheduling of allocation of a time slot to another radio communication device based on the radio signal, communication between the radio communication device and the another radio communication device being executed using time division multiplexing in the first communication mode, and communication between the radio communication device and the another radio communication device being executed using a competitive access method in the second communication mode.

Radio communication device, method for controlling radio communication, and radio communication system

A calculation unit computes, based on subsequent information that is added to data transmitted from a terminal device and indicates the presence or absence of untransmitted data reserved in the terminal device when transmitting the data, the number of data in which untransmitted data exists among the certain number of data previously transmitted from the terminal device. A time slot assignment control unit controls the assigned size of a time slot to the terminal device based on the number of the data, in which untransmitted data exists, computed by the calculation unit. A data processing unit notifies the terminal device of the assigned size of the time slot determined by the time slot assignment control unit.

Base station device, radio communication system, and base station device control method

A wireless communication system includes first and second wireless communication apparatuses. The first wireless communication apparatus includes a plurality of communication units that perform communication in different frequency bands. The plurality of communication units transmits the same control signal and data in the different frequency bands to keep allocation of communication slots for the second wireless communication apparatus on a plurality of paths. When detecting a communication failure while connecting to and communicating with one communication unit through one path, the second wireless communication apparatus switches to another communication unit and continues the communication through another path.

Wireless communication system and wireless communication apparatus

A wireless communication system that includes a hub and multiple nodes is provided. The nodes include a wireless communication control unit that acquires, during a predetermined communication time period, a signal transmitted to the hub by a node; an RSSI calculating unit that calculates propagation information from the signal acquired by the wireless communication control unit; and an RSSI table creating unit that transmits the calculated propagation information to the hub. The hub includes a wireless communication control unit that receives propagation information transmitted by each of the nodes and an RSSI table aggregating unit that aggregates the received propagation information.

Wireless communication system, slave station device, master station device, and wireless communication system control method

A wireless communication device, including a radio transceiver data configured to transmit and to receive data packets to and from a base station, and a processor configured to compute a proportional hidden standby time being computed on the basis of at least two of from among a proportional exposed communication time, a proportional exposed collision time, and a proportional exposed standby time, to compute a predicted PER from the proportional hidden standby time computed; to compute a threshold value for the number of retransmission attempts on the basis of the predicted PER computed, and to cause the radio transceiver to repeat transmission of a data packet to the base station until the number of transmissions exceeds the threshold value computed in the case of failed transmission of a data packet to the base station by the radio transceiver.

Wireless communication device and wireless communication device control method

A mobile communication terminal used in a mobile communication system providing mobile communicating service in a first frequency band is disclosed. The mobile communication terminal comprises a first signal processing circuit for processing signals for the mobile communication service; a second signal processing circuit for processing signals for radio tag communicating in a second frequency band; and an antenna commonly used by the first and second signal processing circuits. The impedance of the antenna is matched with the first signal processing circuit in the first frequency band and matched with the second signal processing circuit in the second frequency band.

Mobile communication terminal having antenna commonly used by first and second circuits, with impedance matched to first or second frequency band

An IQ imbalance correction method includes transmitting a plurality of pairs of RF training signals in installments by pairing RF training signals symmetric with respect to a center frequency on a frequency axis; setting a reception local frequency to change to a frequency that is suitable to receive, via an internal path, each of the plurality of pairs of RF training signals transmitted in installments, and suitable to convert the each of the plurality of pairs of RF training signals into IF training signals; and performing quadrature demodulation on the IF training signals, respectively, in a digital circuit area to generate BB training signals.

IQ imbalance correction method in a wireless communication device including a quadrature modulation/demodulation function

A wireless communications node, being included in a multi-hop route starting from a source node and terminating at a destination node, has a receiving part configured to receive signals including transmission data prepared by the source node and transferring the received signals to a succeeding node, a preparing part configured to prepare source node data including at least identification data of the source node based on a predetermined portion of the transmission data, and a reporting part configured to report the source node data and relay data to a management node that manages cost data of plural nodes included in an ad hoc network. The relay data include the cost data and station data including at least identification data of the wireless communications node.

Wireless communications node used in AD HOC network and method thereof

A phase tracking circuit includes a divider part dividing an input signal that includes data sub-carriers and pilot sub-carriers into groups so that each of the groups includes at least one of the pilot sub-carriers, and a correcting part correcting phases of data sub-carriers of the input signal included in one of the groups on the basis of an amount of phase rotation of the at least one of the pilot sub-carriers included in the above one of the groups.

Phase tracking circuit and radio receiver using the same

In a wireless communication apparatus in a time division duplex system, a transmission signal generation unit generates a transmission signal. A power amplifying device amplifies the generated transmission signal. A control signal generation device generates a drain voltage control signal for control of the drain voltage of the power amplifying device, and a gate voltage control signal for control of the gate voltage of the power amplifying device. The switch unit switches off the drain power supply of the power amplifying device during reception in the time division duplex system according to the drain voltage control signal. In addition, the power amplifying device sets a higher gate voltage during reception in the time division duplex system higher than during transmission according to the gate voltage control signal.

Wireless communication apparatus, power amplifier control method, and power amplifier control apparatus

A disclosed group delay characteristic correcting device corrects group delay characteristics of an analog low-pass filter used to remove aliasing of a digital-analog converter or an analog-digital converter. The group delay characteristic correcting device includes a digital signal processing unit configured to have an all-pass phase circuit at a stage previous to the digital-analog converter or at a stage subsequent to the analog-digital converter so as to correct the group delay characteristics of the analog low-pass filter.

Group delay characteristic correcting device and group delay characteristic correcting method

A MIMO wireless communication system and wireless communication apparatuses are disclosed that increase the practically usable communication channel capacity in the Shannon channel capacity that determines the ratio of maximum signal transmission speed to frequency. Each wireless communication apparatus includes antenna units that transmit and receive radio frequency signals, and a weight controlling unit that provides weights with respect to the antenna units. The antenna units are formed by adaptive array antenna units that can change the directivity by varying weights with respect to antenna elements. The weight controlling unit includes an eigenvalue calculating unit that calculates the eigenvalues of a matrix HH* (H being a channel matrix), an inverse calculation unit that calculates such a channel matrix H' as to have all eigenvalues within a predetermined range that includes the average value of the calculated eigenvalues, and a directivity adjusting unit that adjusts the adaptive array antenna directivity so that the current channel matrix H approaches the calculated channel matrix H&#x2032;.

MIMO wireless communication system and wireless communication apparatuses

A radar equipment of the present invention amplifies a reception signal with feedback based on the delay amount obtained from the correlation detection result. Accordingly, it becomes possible to maintain the reception signal (demodulated signal) level to a proper level depending on the distance to the target, and accurate measurement can be achieved with high precision. Namely, the reception signal is amplified depending on the distance to the target, and the reception signal level is made within a tolerable input level range of a logic circuit for performing correlation calculation. In particular, during tracking the target, even when a reflected signal is received with abrupt level variation caused by noise or a reflected signal from an object other than the target, incorrect detection of the target can be avoided by disabling the correlation calculation.

Growing community of inventors

Kawasaki, Japan

Kaoru Yokoo