Abstract: An OFDM transmitter includes, an allocation unit configured to allocate a first pilot signal and a first data signal respectively to at least one first pilot subcarrier and first data subcarriers within a subcarrier group that is identical among transmitters, and to allocate a second pilot signal and a second data signal respectively to at least one second pilot subcarrier and second data subcarriers outside the subcarrier group, a multiplier to multiply the first pilot signal and the first data signal by complex numbers set for the subcarriers, a modulator to subject the first pilot signal and the first data signal multiplied by the complex numbers and the second pilot signal and the second data signal to OFDM modulation in order to generate an OFDM signal, and a transmission unit configured to transmit the generated OFDM signal.

Abstract: According to one embodiment, a wireless communication apparatus includes a first timer, a generation unit, a transmitter, a receiver and a control unit. The first timer is configured to periodically measure a first time interval. The generation unit is configured to generate a connection request frame. The transmitter is configured to transmit the connection request frame. The receiver is configured to receive a response signal provided in response to the connection request frame. The control unit is configured to control the transmitter and the receiver in such a manner that iterative attempts are made to carry out a transmission of the connection request frame and a wait for reception of the response signal during the first time interval measured by the first timer.

Abstract: According to one embodiment, a wireless communication apparatus includes a wireless unit and a control unit. The wireless unit is configured to set, for each period, a transmit state including a first period for transmitting a connection request to establish connection or a receive state including a second period for receiving a connection request and to transmit or receive a signal, both lengths of the first period and the second period being equal. The control unit is configured to control the wireless unit to operate in one of a transmit mode, a receive mode and a transceive mode. The control unit causes the wireless unit to operate in the receive mode or the transceive mode before a trigger signal is externally input, and to operate in the transmit mode if the trigger signal is input.

Abstract: According to one embodiment, a wireless communication apparatus includes following units. The first timer measures first time intervals. The second timer measures second time intervals. The time interval selection unit selects a second time interval among second time intervals included in each first time interval. The control unit controls the transmitting unit and the receiving unit to operate, during the selected second time interval, in a first operational state in which a transmission of a connection request signal and a wait for reception of a response signal are repeatedly performed, and to operate, during each of the second time intervals other than the selected second time interval, in a second operational state in which a wait for reception of a connection request signal transmitted by another apparatus is performed for a third time interval shorter than each of the second time intervals.

Abstract: In an OFDM transmitter included in a first service area, an orthogonal-code-pattern multiplication unit multiplies pilot channel signals belonging to any subcarrier group by an orthogonal code which is different from that for one or a plurality of OFDM transmitters adjacent to the OFDM transmitter included in the first service area, or a subcarrier assignment unit assigns pilot channel signals to pilot subcarriers which are common to a plurality of OFDM transmitters and based on a pilot arrangement notified in advance by a control station to all OFDM transmitters included in the first service area.

Abstract: A radio communication apparatus includes a first acquisition unit configured to acquire a first frequency use status of a first frequency band having a first center frequency, a second acquisition unit configured to acquire a second frequency use status of a second frequency band having a second center frequency which is a value M/N times (M and N are natural numbers, and M?N) of the first center frequency, and a decision unit configured to determine whether a harmonic is detected in the first frequency band using the first frequency use status and the second frequency use status, and to decide, if it is determined that the harmonic is detected, a radio communication parameter in the first frequency band so as to use a frequency band used by the harmonic in radio communication.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: According to an aspect of the present invention, there is provided with a radio communication method using an OFDMA scheme for uplink communication from a plurality of radio terminals to a base station, including: detecting communication states of the radio terminals; and arranging null subcarriers between subcarriers used by the radio terminals to which frequency bands neighboring on the frequency domain are assigned, depending on the communication states of the radio terminals.

Abstract: The transmitter includes a first bit generator, a modulator, a second bit generator and a bit converter. The first bit generator generates bits to be transmitted based on the first wireless scheme. The modulator for the first wireless scheme performs at least amplitude modulation of a multiple level on the bits generated by the first bit generator. The second bit generator generates a bit to be transmitted based on the second wireless scheme. The bit converter converts the bit generated by the second bit generator and inputs converted bits to the modulator wherein the bit converter converts the bit generated by the second bit generator so that a signal showing High in the second wireless scheme is modulated to amplitude of a high level in the multiple level in the modulator.

Abstract: According to one embodiment, a apparatus includes a coil, a clock generator, an echo transmitter, a carrier generator, a clock transmitter, a regenerator, an receiver, a reconstructor, a detector, and a controller. The echo transmitter generates and transmits an echo transmission signal synchronously with a clock signal generated by the clock generator to wirelessly transmit an echo signal output from the col. The carrier generator generates a carrier signal have a frequency within a variable range. The clock transmitter wirelessly transmits a clock transmission signal. The regenerator regenerates the clock signal based on the transmitted clock transmission signal. The receiver extracts the echo signal synchronously with the regenerated clock signal from the transmitted echo transmission signal. The detector detects a frequency of an interference wave.

Abstract: In one embodiment, an MRI apparatus includes first and second clock generators, a pulse generator, transmission and reception coils, pulse and phase detectors, and a corrector. The pulse generator generates an excitation pulse signal based on a clock signal generated by the first clock generator. The reception coil outputs a radio frequency signals corresponding to an excitation pulse transmitted from the transmission coil or an MR echo. The converter digitizes, synchronously with a clock signal generated by the second clock generator, the radio frequency signal, to obtain radio frequency data. The pulse detector detects excitation pulse data corresponding to the excitation pulse from the radio frequency data. The phase detector detects a phase of a pulse indicated by the detected excitation pulse data. The corrector corrects the radio frequency data based on the detected phase, to compensate for a phase offset which occurs in the echo during the digitization.

Abstract: According to one embodiment, an apparatus includes a control unit and a coil unit. The control unit generates a first clock signal, generates a data signal to indicate an operating condition, modulates the first clock signal by the data signal to obtain a modulated signal, generates a clock transmission signal including the modulated signal, and emits the clock transmission signal. The coil unit converts the clock transmission signal into an electric signal, detects the modulated signal from the clock transmission signal, generates a second clock signal synchronous with the first clock signal from the modulated signal, detects an MR signal generated in a subject, digitizes, synchronously with the second clock signal, the MR signal, detects the data signal from the detected modulated signal by using of the second clock signal, controls the operating condition of the coil unit to be the operating condition indicated by the data signal.

Abstract: According to one embodiment, an MRI apparatus includes a probe unit and a control/imaging unit. The probe unit includes an probe, an converter, an compressor and a transmitter. The control/imaging unit includes a receiver, an expander and an reconstructor. The probe detects an RF echo signal generated in a subject by a magnetic resonance phenomenon. The converter digitizes the detected signal. The compressor compresses the digitized signal in accordance with a predetermined compression parameter to obtain a compressed signal. The transmitter generates a transmission signal to wirelessly transmit the compressed echo signal and sends the transmission signal to a radio channel. The receiver receives the transmission signal and extracts the compressed signal from the received signal. The expander expands the extracted compressed signal in accordance with the parameter to obtain the RF echo signal. The reconstructor generates a video signal regarding the subject on the basis of the obtained signal.

Abstract: An OFDM transmitter includes, a data signal generator which generates a data signal by modulating a bit string obtained by channel coding, a pilot signal generator which generates a pilot signal, an allocation unit which allocates the pilot signal and data signal to a pilot subcarrier and a data subcarrier, a multiplier which multiples the first pilot signal and the first data signal by complex numbers for subcarrier group formed of specific pilot subcarrier of the pilot subcarriers and specific data subcarrier of the data subcarriers, a modulator which performs OFDM modulation on the second pilot signal and the second data signal to generate an OFDM signal, and a transmitting unit which transmits the OFDM signal.

Abstract: A method of transmitting OFDM signals including, allocating a first pilot signal and a first data signal which are both common among OFDM transmitters respectively to at least one first pilot subcarrier and first data subcarriers within a specific time-frequency domain that is common among the OFDM transmitters and different among wireless transmitting units, allocating a second pilot signal and a second data signal respectively to second pilot subcarrier and second data subcarriers outside the time-frequency domain, multiplying the first pilot signal and the first data signal by a complex number set for the time-frequency domain, generating an OFDM signal by performing OFDM modulation on the first pilot signal and the first data signal multiplied by the complex number and the second pilot signal and the second data signal, and transmitting the OFDM signal.

Abstract: According to an aspect of the present invention, there is provided with a radio communication method using an OFDMA scheme for uplink communication from a plurality of radio terminals to a base station, including: detecting communication states of the radio terminals; and arranging null subcarriers between subcarriers used by the radio terminals to which frequency bands neighboring on the frequency domain are assigned, depending on the communication states of the radio terminals.

Abstract: A modulator includes a first input configured to input a first bit string; a first modulating device configured to modulate the inputted first bit string at a first bit rate; a second input configured to input a second bit string; a second modulating device configured to modulate the inputted second bit string at a second bit rate which is lower than the first bit rate; and an output configured to output a modulated signal including the modulated first bit string and the modulated second bit string.

Abstract: In an OFDM transmitter included in a first service area, an orthogonal-code-pattern multiplication unit multiplies pilot channel signals belonging to any subcarrier group by an orthogonal code which is different from that for one or a plurality of OFDM transmitters adjacent to the OFDM transmitter included in the first service area, or a subcarrier assignment unit assigns pilot channel signals to pilot subcarriers which are common to a plurality of OFDM transmitters and based on a pilot arrangement notified in advance by a control station to all OFDM transmitters included in the first service area.

Abstract: An apparatus including a probe unit and a control/imaging unit, the probe unit including a converter converting a sampled magnetic-resonance signal into a digital signal, a first transmitter converting the digital signal into a first-radio signal, a first receiver receiving a second-radio signal, and performing detection on the second-radio signal to obtain a first-received signal, and a clock-regeneration unit regenerating a clock component from the first-received signal to generate a regenerated-clock signal, the control/imaging unit including a second-receiver receiving the first-radio signal to obtain a second-received signal, a data processor performing data processing on the second-received signal in synchronism with a reference-clock signal to obtain a video signal, and a second transmitter including a modulator modulating a carrier wave using the reference-clock signal, the second transmitter converting the reference-clock signal into the second-radio signal and transmitting the second-radio signal th