Abstract: A first radio signal is received that was transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna. The first radio signal is converted to a first orthogonal frequency division multiplexing (OFDM) frame signal, and the second radio signal is converted to a second OFDM frame signal. The first OFDM frame signal includes a grid of multiple frequency subcarriers and time periods, each time period with the frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes first OFDM symbols. A first OFDM symbol is carried on frequency subcarriers during a time period, and the first OFDM frame includes first reference OFDM symbols located at corresponding time-frequency resource elements in the grid. Each resource element is defined by a one of the frequency subcarriers and one of the time periods.

Abstract: A transmitting apparatus includes an OFDM modulator that generates a first modulation symbol by modulating a first information signal using a first modulation scheme, a signal point of the first modulated information signal being arranged at a first position in an in-phase quadrature-phase plane and a second modulation symbol by modulating a second information signal using the first modulation scheme, and by changing a second position at which a signal point of the modulated second information signal is arranged to a third position in the in-phase quadrature-phase plane, wherein the third position is different from the first position. An OFDM modulation signal includes the first modulation symbol and the second modulation symbol, wherein the OFDM modulation signal comprises a plurality of subcarriers. A transmitter transmits the OFDM modulation signal.

Abstract: A transmission apparatus includes a plurality of orthogonal frequency division multiplexing (OFDM) modulation signal generators, which generate a first OFDM modulation signal and a second OFDM modulation signal. The transmission apparatus also includes a transmitter that transmits the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

Abstract: A wireless communication method is provided for a transmission apparatus that transmits an OFDM (orthogonal frequency division multiplexing) signal using a communication band that comprises a plurality of subcarrier groups each including a plurality of subcarriers. The method includes specifying which subcarrier group and how many subcarriers are to be used to transmit the OFDM signal and determining a configuration of a transmission frame, generating the OFDM signal by mapping data symbols according to the determined configuration of the transmission frame, and transmitting the generated OFDM signal. The number of subcarriers to be used to transmit the OFDM signal is variable, the OFDM signal may be generated using a plurality of modulation schemes including QPSK and 16QAM, and a plurality of mapping patterns are prepared for each of the plurality of modulation schemes.

Abstract: A plurality of modulation signals is generated. Each of the plurality of modulation signals includes a pilot symbol sequence having a plurality of pilot symbols. Each pilot symbol sequence is inserted at a same temporal point in each modulation signal, and each pilot symbol in the pilot symbol sequence has a non-zero amplitude. A quantity of the plurality of pilot symbols in each pilot symbol sequence is greater than or equal to a quantity of the plurality of modulation signals to be transmitted. The plurality of modulation signals are transmitted in an identical frequency band from a plurality of antennas. Each of the transmitted plurality of modulation signals includes transmission data and one of the pilot symbol sequences.

Abstract: A transmission apparatus includes orthogonal frequency division multiplexing (OFDM) modulation signal generating circuitry. The circuitry generates a first OFDM modulation signal by inserting symbols for demodulation in a first plurality of subcarriers at a first time and in a second plurality of sub-carriers at a second time adjacent to the first time, the symbols for demodulation being reception processing reference symbols of a reception apparatus, and, inserting symbols, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time.

Abstract: Modulated signal A is transmitted from a first antenna, and modulated signal B is transmitted from a second antenna. As modulated signal B, modulated symbols S2(i) and S2(i+1) obtained from different data are transmitted at time i and time i+1 respectively. In contrast, as modulated signal A, modulated symbols S1(i) and S1(i)? obtained by changing the signal point arrangement of the same data are transmitted at time i and time i+1 respectively. As a result the reception quality can be changed intentionally at time i and time i+1, and therefore using the demodulation result of modulated signal A of a time when the reception quality is good enables both modulated signals A and B to be demodulated with good error rate performances.

Abstract: A plurality of modulation signals is generated. Each of the plurality of modulation signals includes a pilot symbol sequence having a plurality of pilot symbols. Each pilot symbol sequence is inserted at a same temporal point in each modulation signal, and each pilot symbol in the pilot symbol sequence has a non-zero amplitude. A quantity of the plurality of pilot symbols in each pilot symbol sequence is greater than or equal to a quantity of the plurality of modulation signals to be transmitted. The plurality of modulation signals are transmitted in an identical frequency band from a plurality of antennas. Each of the transmitted plurality of modulation signals includes transmission data and one of the pilot symbol sequences.

Abstract: Modulated signal A is transmitted from a first antenna, and modulated signal B is transmitted from a second antenna. As modulated signal B, modulated symbols S2(i) and S2(i+1) obtained from different data are transmitted at time i and time i+1 respectively. In contrast, as modulated signal A, modulated symbols S1(i) and S1(i)? obtained by changing the signal point arrangement of the same data are transmitted at time i and time i+1 respectively. As a result the reception quality can be changed intentionally at time i and time i+1, and therefore using the demodulation result of modulated signal A of a time when the reception quality is good enables both modulated signals A and B to be demodulated with good error rate performances.

Abstract: A multi-radar system is configured such that radars A and B perform synchronization so that their transmission timings and frequency bands are substantially the same. For this reason, in a case where the radars A and B operate as bistatic radars, the radars A and B yield the same detection results from reflected waves from a place on a surface of a target T where the detection object regions of the radars A and B overlap. Therefore, the signal-to-noise ratio can be improved by synthesizing the target detection results obtained by the radars A and B operating as bistatic radars. This results in improved target detection performance.

Abstract: A first radio signal is received that was transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna. The first radio signal is converted to a first orthogonal frequency division multiplexing (OFDM) frame signal, and the second radio signal is converted to a second OFDM frame signal. The first OFDM frame signal includes a grid of multiple frequency subcarriers and time periods, each time period with the frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes first OFDM symbols. A first OFDM symbol is carried on frequency subcarriers during a time period, and the first OFDM frame includes first reference OFDM symbols located at corresponding time-frequency resource elements in the grid. Each resource element is defined by a one of the frequency subcarriers and one of the time periods.

Abstract: A transmission apparatus includes processing circuitry that generates a first data sequence representing first data or a second data sequence representing second data different from the first data and selects the first data sequence as an output data sequence. A modulation scheme is determined from a plurality of modulation schemes, and the output data sequence is modulated with the determined modulation scheme. Transmission circuitry transmits the modulated output data sequence. A first time interval associated with selecting the first data sequence for the output data sequence is longer than a second time interval associated with determining the determined modulation scheme.

Abstract: A transmission apparatus includes a plurality of orthogonal frequency division multiplexing (OFDM) modulation signal generators, which generate a first OFDM modulation signal and a second OFDM modulation signal. The transmission apparatus also includes a transmitter that transmits the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

Abstract: A first orthogonal frequency division multiplexing (OFDM) frame signal is generated that includes a grid of multiple frequency subcarriers and multiple time periods. An OFDM symbol is transmitted using multiple frequency subcarriers during a time period and includes known reference OFDM symbols assigned to corresponding time-frequency resource elements in the grid, Each resource element is defined by a one of the multiple frequency subcarriers and one of the multiple time periods. A second orthogonal frequency division multiplexing (OFDM) frame signal is generated that includes a grid of multiple frequency subcarriers and multiple time periods and includes known reference OFDM symbols assigned to corresponding time-frequency resource elements in the grid.

Abstract: A transmission apparatus includes a plurality of antennas and a transmission scheme determination processor that selects one of either a first transmission scheme of transmitting a plurality of signals including a first amount of data in a frame, respectively, from the plurality of antennas, and a second transmission scheme of transmitting a plurality of signals including a second greater amount of data in a frame, respectively, from the plurality of antennas. The apparatus includes a modulation scheme selection processor that selects a modulation scheme among a plurality of modulation schemes and a control processor that controls the transmission scheme determination processor and the modulation scheme selection processor to change the transmission scheme less frequently than the modulation scheme. A transmitter transmits from the plurality of antennas a signal generated based on the selected transmission scheme and the selected modulation scheme.

Abstract: A transmission apparatus includes a plurality of orthogonal frequency division multiplexing (OFDM) modulation signal generators, which generate a first OFDM modulation signal and a second OFDM modulation signal. The transmission apparatus also includes a transmitter that transmits the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

Abstract: A radio transmission apparatus includes a first antenna, a second antenna, and circuitry configured, based on information associated with an estimated communications channel condition, to generate a single modulation signal or a plurality of modulation signals based on the estimated communications channel condition information, and to (i) transmit the single modulation signal from the first antenna or (ii) transmit the plurality of modulation signals which include different information from each other over an identical frequency band from the first antenna and the second antenna at an identical temporal point. The single modulation signal and the plurality of modulation signals contain parameter information indicating a number of modulation signals transmitted at the same time.

Abstract: A plurality of modulation signals is generated. Each of the plurality of modulation signals includes a pilot symbol sequence having a plurality of pilot symbols. Each pilot symbol sequence is inserted at a same temporal point in each modulation signal, and each pilot symbol in the pilot symbol sequence has a non-zero amplitude. A quantity of the plurality of pilot symbols in each pilot symbol sequence is greater than or equal to a quantity of the plurality of modulation signals to be transmitted. The plurality of modulation signals are transmitted in an identical frequency band from a plurality of antennas. Each of the transmitted plurality of modulation signals includes transmission data and one of the pilot symbol sequences.

Abstract: A radio communication apparatus includes a QPSK modulator that modulates transmission data to produce a QPSK modulation signal and a 64QAM modulator that modulates transmission data to produce a 64QAM modulation signal. A radio transmitter receives the QPSK modulation signal and the 64QAM modulation signal and outputs a transmission signal. An average transmission power of the QPSK modulation signal and the 64QAM modulation signal are within a predetermined output power range.

Abstract: A receiver receives, using a plurality of antennas, a multiplexed signal that includes (i) a first OFDM modulation signal with a subcarrier carrying a symbol including multiplex information and a subcarrier carrying a pilot symbol and a subcarrier carrying a data symbol and (ii) a second OFDM modulation signal with a subcarrier carrying a symbol including multiplex information and a subcarrier carrying the pilot symbol and a subcarrier carrying the data symbol. A decoder uses the symbol including multiplex information and decodes the data symbol.