Abstract: A first device includes: a first reference signal source; a first transmitting/receiving unit which transmits two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source; and a calculating unit. A second device includes: a second reference signal source configured to be operated independently from the first reference signal source; and a second transmitting/receiving unit configured to transmit two or more second carrier signals and receive two or more first carrier signals using an output of the second reference signal source. A frequency group of two or more first carrier signals and a frequency group of two or more second carrier signals differ from each other. The calculating unit calculates a distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.

Abstract: A distance measurement apparatus includes a calculation unit configured to calculate, based on phase information acquired by two distance measurement units at least one of which is movable, a distance between the two distance measurement units. One of the two distance measurement units includes an RSSI estimation unit configured to estimate, from respective three receiving signal intensities of three first carrier signals or respective three receiving signal intensities of three second carrier signals, the receiving signal intensity of a frequency having an average value, and a fading correction value calculation unit configured to calculate a fading correction value for the distance from the receiving signal intensity of a lowest frequency and the receiving signal intensity of a highest frequency. The calculation unit calculates the distance using a phase detection result obtained by receiving the three first carrier signals and the three second carrier signals and the fading correction value.

Abstract: A distance measuring device includes a calculating section that calculates, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first transceiver that transmits three or more first carrier signals and receives three or more second carrier signals using an output of a first reference signal source. The second device includes a second transceiver that transmits the three or more second carrier signals and receives the three or more first carrier signals using an output of a second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals and corrects the calculated distance based on information concerning an amplitude ratio of the first carrier signals received by the second transceiver.

Abstract: A distance measuring device includes a calculating section that calculates, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first transceiver that transmits three or more first carrier signals and receives three or more second carrier signals using an output of a first reference signal source. The second device includes a second transceiver that transmits the three or more second carrier signals and receives the three or more first carrier signals using an output of a second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals and corrects the calculated distance based on information concerning an amplitude ratio of the first carrier signals received by the second transceiver.

Abstract: A distance measurement system for transmitting and receiving a distance measurement signal including a phase detection signal between first and second devices and calculating a distance between the devices based on a phase detection result of the received phase detection signal includes a modulation circuit configured to generate the distance measurement signal including a modulated signal obtained by modulating an identification signal, a transmission circuit configured to transmit the distance measurement signal, a reception circuit configured to receive the distance measurement signal, a demodulation circuit configured to demodulate the modulated signal in the received distance measurement signal, and a control circuit configured to judge a restored state of the identification signal obtained from a demodulation result of the demodulation circuit.

Abstract: A wireless system of an embodiment includes two wireless apparatuses. Each wireless apparatus includes: a reception circuit configured to receive a signal in a predetermined frequency band; a carrier sensing circuit configured to perform carrier sensing in which, in response to reception of a predetermined signal, signals on a plurality of channels included in the predetermined frequency band are simultaneously received, and use states of the respective channels are detected based on the received signals on the respective channels; and an idle channel determiner configured to determine an idle channel from the plurality of channels based on the use states of the respective channels detected in the carrier sensing circuit according to a predetermined determination rule.

Abstract: A distance measuring device includes a calculating section that calculates, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first transceiver that transmits three or more first carrier signals and receives three or more second carrier signals using an output of a first reference signal source. The second device includes a second transceiver that transmits the three or more second carrier signals and receives the three or more first carrier signals using an output of a second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals and corrects the calculated distance based on information concerning an amplitude ratio of the first carrier signals received by the second transceiver.

Abstract: A distance measuring device includes a calculating section configured to calculate, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first reference signal source and a first transceiver configured to transmit two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source. The second device includes a second reference signal source configured to operate independently from the first reference signal source and a second transceiver configured to transmit the second carrier signals and receives the first carrier signals using an output of the second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals.

Abstract: A reception device includes a low noise amplifier that amplifies a radio signal by a first gain, a variable gain amplifier that amplifies an output of the low noise amplifier by a second gain, an analog-to-digital converter that converts an output of the variable gain amplifier into a digital signal, a gain controller, and a saturation detection unit. The gain controller, when an amplitude of the radio signal exceeds a predetermined value, controls the first and second gains according to the amplitude of the radio signal, and completes the control within a predetermined period. The saturation detection unit detects saturation of the analog-to-digital converter based on the output of the low noise amplifier or the digital signal. The gain controller, after controlling the first and second gains a first time and the saturation is detected by the saturation detection unit, controls the first and second gains a second time.

Abstract: A reception device includes a low noise amplifier that amplifies a radio signal by a first gain, a variable gain amplifier that amplifies an output of the low noise amplifier by a second gain, an analog-to-digital converter that converts an output of the variable gain amplifier into a digital signal, a gain controller, and a saturation detection unit. The gain controller, when an amplitude of the radio signal exceeds a predetermined value, controls the first and second gains according to the amplitude of the radio signal, and completes the control within a predetermined period. The saturation detection unit detects saturation of the analog-to-digital converter based on the output of the low noise amplifier or the digital signal. The gain controller, after controlling the first and second gains a first time and the saturation is detected by the saturation detection unit, controls the first and second gains a second time.

Abstract: According to one embodiment, a receiver, which is configured to receive a radio signal having a preamble including a synchronization pattern and a payload containing data, includes an antenna, a low noise amplifier, a down-conversion module, a variable gain amplifier, an auto gain controller, a synchronization acquisition module, and a demodulator. The antenna is configured to receive the radio signal. The low noise amplifier is configured to amplify an output from the antenna by applying a first variable gain. The down-conversion module is configured to down-convert an output from the low noise amplifier. The variable gain amplifier is configured to amplify an output from the down-conversion module by applying a second variable gain. The auto gain controller is configured to, in accordance with strength of the radio signal, firstly adjust the first variable gain, and after fixing the first variable gain, adjust the second variable gain.

Abstract: According to one embodiment, a receiver, which is configured to receive a radio signal having a preamble including a synchronization pattern and a payload containing data, includes an antenna, a low noise amplifier, a down-conversion module, a variable gain amplifier, an auto gain controller, a synchronization acquisition module, and a demodulator. The antenna is configured to receive the radio signal. The low noise amplifier is configured to amplify an output from the antenna by applying a first variable gain. The down-conversion module is configured to down-convert an output from the low noise amplifier. The variable gain amplifier is configured to amplify an output from the down-conversion module by applying a second variable gain. The auto gain controller is configured to, in accordance with strength of the radio signal, firstly adjust the first variable gain, and after fixing the first variable gain, adjust the second variable gain.

Abstract: A wireless communication apparatus including a first semiconductor integrated circuit and a second semiconductor integrated circuit is provided. The first semiconductor integrated circuit includes an activation control unit that sets a first activation control signal and a second activation control signal in response to whether or not a wake-up signal, and a reception processing unit that transitions into an operation state from a sleep state in response to the first activation control signal and demodulates the wireless signal in the operation state. The second semiconductor integrated circuit transitions into an operation state from a sleep state in response to the second activation control signal, and processes a demodulated signal which is output from the first semiconductor integrated circuit in the operation state.

Abstract: According to an embodiment, a DC offset canceller includes a first DA converter, a first adder, an amplifier, a comparator, an averaging circuit, and a successive approximation register. The first DA converter is configured to DA-convert first correction data into a first correction voltage. The first adder is configured to add an input signal and the first correction voltage to output a first added signal. The amplifier is configured to amplify the first added signal to output an amplified signal. The comparator is configured to compare the amplified signal and a reference voltage to output a comparison result. The averaging circuit is configured to receive the comparison results of the comparator to obtain a majority decision result by performing majority decision on logical values of the comparison results in a predetermined time period.

Abstract: According to an embodiment, a DC offset canceller includes a first DA converter, a first adder, an amplifier, a comparator, an averaging circuit, and a successive approximation register. The first DA converter is configured to DA-convert first correction data into a first correction voltage. The first adder is configured to add an input signal and the first correction voltage to output a first added signal. The amplifier is configured to amplify the first added signal to output an amplified signal. The comparator is configured to compare the amplified signal and a reference voltage to output a comparison result. The averaging circuit is configured to receive the comparison results of the comparator to obtain a majority decision result by performing majority decision on logical values of the comparison results in a predetermined time period.

Abstract: A cognitive radio system includes: a state detecting device that scans a frequency band allocated to another radio system than the cognitive radio system to detect a first use-state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-state of the frequency band allocated to the other radio system, the second server configured to provide second information relating to the second use-state to the second gathering unit; and a notifying unit that notifies a terminal device in the cognitive radio system of information of an available channel based on the first information and the second information.

Abstract: A wireless communication system including at least one wireless base station and two or more wireless terminals, and each of the wireless terminals can communicate with the wireless base station or directly communicate with another wireless terminal. The wireless base station observes reception frames from the wireless terminals, and transmits to one of the wireless terminals a start frame for starting direct communication of the wireless terminal concerned with another wireless terminal on the basis of the reception information of the reception frames.

Abstract: A radio communication system in which a plurality of wireless terminals form wireless channels separately between a common base station unit and wireless terminals and communicate with the base station unit, the radio communications system comprises quality managing section manages communication quality of wireless channel for each of wireless terminals by assigning occupied band of wireless channel on basis of a predetermined parameter, channel securing section secures continuously wireless channel for at least one wireless terminal by controlling data rate of the wireless channel according to change in channel state between wireless sections, and rate change detecting section supplies trigger information to quality managing section when data rate of at least one wireless channel changes as a result of control performed by channel securing section, the quality managing section, when being given trigger, updating occupied band assigned state of the wireless channel for each of wireless terminals.

Abstract: A receiving apparatus for wireless communication is provided with an offset value calculating unit configured to time-average the received signal from the orthogonal demodulator to the demodulator to detect a DC offset value, and feed back the DC offset value to a signal channel from the orthogonal demodulator to the demodulator, an automatic gain controlling unit configured to calculate and time-average a power of the received signal from the orthogonal demodulator to the demodulator to generate an AGC signal, and control a gain of an amplifier, and a controlling unit configured to control to interlock (synchronize) a DC offset value detecting operation of the offset value calculating unit and an AGC signal generating operation of the automatic gain controlling unit.

Abstract: A radio communication apparatus for transmitting and receiving a plurality of frames to and from another radio communication apparatus, comprises a first transmitting unit configured to sequentially transmit a plurality of frames at a plurality of transmission rates to the another radio communication apparatus, a second transmitting unit configured to transmit, to the another radio communication apparatus, an inquiry signal for inquiring which frames included in the frames are received by the another radio communication apparatus, a receiving unit configured to receive, from the another radio communication apparatus, information indicating which frames included in the frames are received or fail to be received, and a rate setting unit configured to set the first transmitting unit to a transmission rate used for next transmission of frames to the another radio communication apparatus, based on the received information.