Communication system, transmission apparatus, and receiving apparatus
AssigneeCanon Kabushiki Kaisha
InventorMakoto Umehara
Life of this patent
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Abstract
A transmission apparatus for performing an orthogonal frequency division multiplexing (OFDM) transmission generates an OFDM symbol in which a modulation parameter used at a time of transmitting data is arranged in a subcarrier of a direct current component and transmits a transmission frame including the generated OFDM symbol. A receiving apparatus calculates an average value in an effective symbol period within the OFDM symbol included in the transmission frame received, extracts the modulation parameter arranged in the subcarrier of the direct current component based on the calculated average value, and performs OFDM demodulation processing using the extracted modulation parameter.
Claims15
A communication system comprising:
- a transmission apparatus comprising:
- a generation unit configured to generate an orthogonal frequency division multiplexing (OFDM) symbol in which a modulation parameter at a time of data transmission is arranged in a subcarrier of a direct current component;
- an adjustment symbol addition unit configured to add an adjustment symbol having a time length based on fluctuations in a clock signal to a rear end of the OFDM symbol;
- and
- a transmission unit configured to transmit a transmission frame including the OFDM symbol and the adjustment symbol;
- and
- a receiving apparatus comprising:
- a calculation unit configured to calculate an average value within an effective symbol period in the OFDM symbol included in the transmission frame received by the receiving apparatus;
- an extraction unit configured to extract the modulation parameter arranged in the subcarrier of the direct current component based on the calculated average value;
- and
- a demodulation unit configured to perform OFDM demodulation processing using the modulation parameter extracted by the extraction unit,
- wherein the OFDM symbol includes an effective symbol and a guard interval, and the modulation parameter includes timing information for the effective symbol.
A transmission apparatus for performing orthogonal frequency division multiplexing (OFDM) transmission, the transmission apparatus comprising:
- a generation unit configured to generate an OFDM symbol arranging a modulation parameter used at a time of data transmission in a subcarrier of a direct current component;
- an adjustment symbol addition unit configured to add an adjustment symbol having a time length based on fluctuations in a clock signal to a rear end of the OFDM symbol;
- and
- a transmission unit configured to transmit a transmission frame including the OFDM symbol and the adjustment symbol,
- wherein the OFDM symbol includes an effective symbol and a guard interval, and the modulation parameter includes timing information for the effective symbol.
A receiving apparatus for performing orthogonal frequency division multiplexing (OFDM) reception, the receiving apparatus comprising:
- a receiving unit configured to receive a transmission frame including an OFDM symbol arranging time information related to a data transmission frame in a subcarrier of a direct current component and an adjustment symbol having a time length based on fluctuations in a clock signal added to a rear end of the OFDM symbol;
- a discriminating unit configured to discriminate an average value in an effective symbol period within the OFDM symbol included in the received transmission frame;
- a determining unit configured to determine the time information related to the data transmission frame based on the discriminated average value;
- and
- a demodulation unit configured to perform OFDM demodulation processing using the time information determined by the determining unit.
A control method for performing orthogonal frequency division multiplexing (OFDM) communication, the control method comprising:
- generating an OFDM symbol in which a modulation parameter at a time of data transmission is arranged in a subcarrier of a direct current component;
- adding an adjustment symbol having a time length based on fluctuations in a clock signal to a rear end of the OFDM symbol;
- transmitting a transmission frame including the OFDM symbol and the adjustment symbol;
- receiving the transmission frame;
- calculating an average value in an effective symbol period within the OFDM symbol included in the received transmission frame;
- extracting the modulation parameter arranged in the subcarrier of the direct current component based on the calculated average value;
- and
- performing OFDM demodulation processing using the extracted modulation parameter,
- wherein the OFDM symbol includes an effective symbol and a guard interval, and the modulation parameter includes timing information for the effective symbol.
A control method of a transmission apparatus for performing orthogonal frequency division multiplexing (OFDM) transmission, the control method comprising:
- generating an OFDM symbol in which a modulation parameter used at a time of transmitting data is arranged in a subcarrier of a direct current component;
- adding an adjustment symbol having a time length based on fluctuations in a clock signal to a rear end of the OFDM symbol;
- and
- transmitting a transmission frame including the generated OFDM symbol and the adjustment symbol,
- wherein the OFDM symbol includes an effective symbol and a guard interval, and the modulation parameter includes timing information for the effective symbol.
A control method of a receiving apparatus for performing orthogonal frequency division multiplexing (OFDM) reception, the control method comprising:
- receiving a transmission frame including an OFDM symbol arranging time information related to a data transmission frame in a subcarrier of a direct current component and an adjustment symbol having a time length based on fluctuations in a clock signal added to a rear end of the OFDM symbol;
- discriminating an average value in an effective symbol period within the OFDM symbol included in the received transmission frame;
- determining the time information related to the data transmission frame based on the discriminated average value;
- and
- performing OFDM demodulation processing using the time information.
Dependencies are inferred from the claim text.