Abstract: A radar apparatus includes: a transmitting antenna; a receiving antenna; transmitting circuitry; receiving circuitry; a storage; and control circuitry which selects one of a plurality of spread codes. A radar signal includes a plurality of periodic frames. Each of the frames includes first and second segments. The first segment includes a first spread signal which is obtained by multiplication of a predetermined reference signal by at least a part of the selected spread code. The second segment includes a second spread signal which is obtained by multiplication of the identification code by at least the part of the selected spread code.

Abstract: Provided is an OFDM reception apparatus that can reduce, even in an environment where the influence of noises is strong, this influence of the noises, thereby improving the precision of detecting a carrier frequency error. In this apparatus, a filtering unit (151) receives received signals each including a short preamble (STF) in which a plurality of pilot subcarriers are intermittently arranged in the frequency domain and repeatedly arranged in the time domain, and the filtering unit (151) attenuates the frequency components between respective two adjacent ones of the plurality of pilot subcarriers in the frequency domain. A correction unit (154) corrects a carrier frequency error of the received signal on the basis of the signals of the plurality of pilot subcarriers having passed through the filtering unit (151).

Abstract: A preamble generating unit generates first and second synchronization preambles having different numbers of subcarriers. A transmission signal generating unit generates an OFDM transmission signal through time-division multiplexing by using the generated first and second synchronization preambles. A transmission RF unit converts the generated OFDM transmission signal into a radio-frequency OFDM signal and transmits the radio-frequency OFDM signal. The preamble generating unit adds a predetermined dummy period between the first synchronization preamble and the second synchronization preamble.

Abstract: An OFDM receiver apparatus (100) receives a signal that includes an STF having a plurality of pilot subcarriers and a plurality of null subcarriers that are alternately arranged at predetermined frequency intervals in a transmission band and that includes a data part that is time-multiplexed with the STF. A null carrier extraction unit (151) extracts a plurality of null subcarrier frequency signals from the received signal. A power calculation unit (152) detects, based on the levels of the extracted signals, the interference levels of the plurality of subcarriers in the transmission band. A soft decision unit (112) uses the reliability of the plurality of subcarriers, which is calculated based on the detected interference levels, to perform a soft decision of a demodulated signal of the received data part. An error correction unit (113) performs, based on the result of the soft decision, an error correction, thereby reconstructing the data.

Abstract: An interfering wave is detected using, in a received signal including a preamble and a control signal field, a plurality of symbols including a symbol configuring the preamble and a symbol configuring the control signal field. The received signal has one of a plurality of transmission formats that use at least either a first frequency band or a second frequency band. In a signal quality detector, a symbol differential calculator calculates, in each of the first frequency band and the second frequency band, differences between a certain number of symbols adjacent to one another at predetermined positions in a time domain among the plurality of symbols. A square operator performs square operations on results of the calculation of differences. An interference determiner determines, using results of the square operations, whether each of the first frequency band and the second frequency band includes an interfering wave.

Abstract: A radar apparatus includes: a transmitting antenna; a receiving antenna; transmitting circuitry; receiving circuitry; a storage; and control circuitry which selects one of a plurality of spread codes. A radar signal includes a plurality of periodic frames. Each of the frames includes first and second segments. The first segment includes a first spread signal which is obtained by multiplication of a predetermined reference signal by at least a part of the selected spread code. The second segment includes a second spread signal which is obtained by multiplication of the identification code by at least the part of the selected spread code.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: An OFDM receiver apparatus (100) receives a signal that includes an STF having a plurality of pilot subcarriers and a plurality of null subcarriers that are alternately arranged at predetermined frequency intervals in a transmission band and that includes a data part that is time-multiplexed with the STF. A null carrier extraction unit (151) extracts a plurality of null subcarrier frequency signals from the received signal. A power calculation unit (152) detects, based on the levels of the extracted signals, the interference levels of the plurality of subcarriers in the transmission band. A soft decision unit (112) uses the reliability of the plurality of subcarriers, which is calculated based on the detected interference levels, to perform a soft decision of a demodulated signal of the received data part. An error correction unit (113) performs, based on the result of the soft decision, an error correction, thereby reconstructing the data.

Abstract: Provided is an OFDM reception apparatus that can reduce, even in an environment where the influence of noises is strong, this influence of the noises, thereby improving the precision of detecting a carrier frequency error. In this apparatus, a filtering unit (151) receives received signals each including a short preamble (STF) in which a plurality of pilot subcarriers are intermittently arranged in the frequency domain and repeatedly arranged in the time domain, and the filtering unit (151) attenuates the frequency components between respective two adjacent ones of the plurality of pilot subcarriers in the frequency domain. A correction unit (154) corrects a carrier frequency error of the received signal on the basis of the signals of the plurality of pilot subcarriers having passed through the filtering unit (151).

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: A preamble generating unit generates first and second synchronization preambles having different numbers of subcarriers. A transmission signal generating unit generates an OFDM transmission signal through time-division multiplexing by using the generated first and second synchronization preambles. A transmission RF unit converts the generated OFDM transmission signal into a radio-frequency OFDM signal and transmits the radio-frequency OFDM signal. The preamble generating unit adds a predetermined dummy period between the first synchronization preamble and the second synchronization preamble.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: An interfering wave is detected using, in a received signal including a preamble and a control signal field, a plurality of symbols including a symbol configuring the preamble and a symbol configuring the control signal field. The received signal has one of a plurality of transmission formats that use at least either a first frequency band or a second frequency band. In a signal quality detector, a symbol differential calculator calculates, in each of the first frequency band and the second frequency band, differences between a certain number of symbols adjacent to one another at predetermined positions in a time domain among the plurality of symbols. A square operator performs square operations on results of the calculation of differences. An interference determiner determines, using results of the square operations, whether each of the first frequency band and the second frequency band includes an interfering wave.

Abstract: There is provided a diversity receiving apparatus, comprising: a first branch (5) for decoding a frequency multiplexing signal in which a carrier group has been multiplexed, thereby outputting a first data carrier and a first pilot carrier; a second branch (6) for decoding a frequency multiplexing signal in which a carrier group has been multiplexed, thereby outputting a second data carrier and a second pilot carrier; a timing adjusting unit (7) for synchronizing processing timing for a carrier group decoded by the first branch (5) and a carrier group decoded by the second branch (6); a combining/selecting unit (8) for combining/selecting the first data carrier and/or the second data carrier; and a control unit (10) for controlling stopping and starting operation of at least one of the first branch (5) and the second branch (6) according to at least one of a receiving status of the first branch (5) and a receiving status of second branch (6).

Abstract: There is provided a diversity receiving apparatus (1) that comprises: a receiving unit (4) for receiving a frequency-division multiplexing signal on which a carrier group is multiplexed; a first demodulating unit (5) for outputting a first data carrier and a first transmission control carrier; a second demodulating unit (6) for outputting a second data carrier and a second transmission control carrier; a timing adjusting unit (7) for synchronizing processing timing of the first demodulating unit (5) and the second demodulating unit (6); a first combining/selecting unit (60) for combining or selecting a first transmission control carrier and a second transmission control carrier; a second combining/selecting unit (8) for combining or selecting a first data carrier and a second data carrier; a decoding unit (13) for decoding a transmission control signal using the transmission control carrier selected by the first combining/selecting unit (60); and a detecting unit (14) for detecting frame synchronization.

Abstract: The symbol rate detector includes a nonlinear processing section configured to perform nonlinear processing on a digitally modulated signal, and to output a processed signal, and a phase-locked loop being in synchronization with the processed signal. The phase-locked loop includes an oscillator configured to generate a signal with a frequency corresponding to a detected symbol rate, a complex multiplier configured to multiply the processed signal by the signal generated by the oscillator, and to output a multiplication result, and a loop filter configured to smooth the multiplication result, and to output the smoothed multiplication result as the detected symbol rate.

Abstract: A device mitigates reduction in reception performance caused by a harmonic component of a clock used for demodulation. The device includes a tuner performing frequency conversion by multiplying a received signal by a signal having a frequency corresponding to a frequency of a desired signal included in the received signal, and outputting the obtained frequency-converted signal; and a demodulation section generating a demodulated signal by demodulating the frequency-converted signal. The demodulation section operates in response to a master clock having a frequency corresponding to the frequency of the desired signal.