Method and apparatus for receiving diversity signals for use in OFDM radio communication system
First Claim
1. A receiving apparatus comprising:
- a plurality of diversity branches, each of said diversity branches including a receiver for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal, a transformer for transforming the orthogonal frequency division multiplexing received signal into a orthogonal frequency division multiplexing received signal frequency spectrum and outputting the orthogonal frequency division multiplexing received signal frequency spectrum, and a channel frequency response calculating unit for calculating a channel frequency response in accordance with the orthogonal frequency division multiplexing received signal frequency spectrum and a reference frequency spectrum; and
a selector unit for selecting the diversity branch that has generated the orthogonal frequency division multiplexing received signal frequency spectrum having a maximum amplitude or a maximum power.
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Abstract
In a diversity receiving apparatus for use in an OFDM transmission radio communication/broadcasting system, OFDM signals are received by a plurality of antennas and are input into a plurality of receivers. The OFDM received signals are further input into a plurality of transformers and are transformed into frequency spectra. A plurality of channel frequency response calculating units calculate channel frequency responses by using the OFDM received signal frequency spectra and a reference frequency spectrum generated in a reference frequency spectrum generator. A plurality of distortion compensators then compensate for the distortions of the OFDM received signal frequency spectra by using the corresponding channel frequency responses. The OFDM received signal frequency spectra output from the first transformers are input into a selector unit as first input signals, while the distortion-compensated OFDM received signal frequency spectra are input into the selector unit as second input signals. The selector unit then selects the second input signal corresponding to the first input signal having the maximum amplitude or the maximum power. A demodulator then demodulates the output signal of the selector unit into a digital signal sequence.
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Citations
37 Claims
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1. A receiving apparatus comprising:
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a plurality of diversity branches, each of said diversity branches including a receiver for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal, a transformer for transforming the orthogonal frequency division multiplexing received signal into a orthogonal frequency division multiplexing received signal frequency spectrum and outputting the orthogonal frequency division multiplexing received signal frequency spectrum, and a channel frequency response calculating unit for calculating a channel frequency response in accordance with the orthogonal frequency division multiplexing received signal frequency spectrum and a reference frequency spectrum; and
a selector unit for selecting the diversity branch that has generated the orthogonal frequency division multiplexing received signal frequency spectrum having a maximum amplitude or a maximum power.
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2. A receiving apparatus comprising:
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a plurality of diversity branches, each of said diversity branches including a receiver for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal, a transformer for transforming the orthogonal frequency division multiplexing received signal into a orthogonal frequency division multiplexing received signal frequency spectrum and outputting the orthogonal frequency division multiplexing received signal frequency spectrum, and a channel frequency response calculating unit for calculating a channel frequency response in accordance with the orthogonal frequency division multiplexing received signal frequency spectrum and a reference frequency spectrum; and
a selector unit for selecting the diversity branch that has generated the channel frequency response having a maximum amplitude or a maximum power. - View Dependent Claims (13, 19, 25)
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3. A receiving apparatus comprising:
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a plurality of receivers, each of said receivers for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal;
a plurality of transformers, each of said transformers for transforming the orthogonal frequency division multiplexing received signal from a corresponding one of the plurality of receivers into a orthogonal frequency division multiplexing received signal frequency spectrum;
at least one reference frequency spectrum generator for generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
a plurality of channel frequency response calculating units, each of said channel frequency response calculating units for calculating a channel frequency response in accordance with the frequency spectrum output from a corresponding one of the plurality of transformers and the reference frequency spectrum;
a distortion compensator for compensating for a distortion of the frequency spectrum output from each of said transformers by using the corresponding channel frequency response;
a selector unit for selecting, from among the frequency spectra output from said transformer applied thereto as first input signals, the first input signals having a maximum amplitude or a maximum power, said outputting, from among the distortion compensated frequency spectra output from said distortion compensated applied thereto as second input signals, the second input signal corresponding to the selected first input signal; and
a demodulator for demodulating the output signal of said selector unit into a digital signal sequence. - View Dependent Claims (8, 14, 20, 26)
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4. A receiving apparatus comprising:
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a plurality of receivers, each of said receivers for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal;
a plurality of transformers, each of said transformers for transforming the orthogonal frequency division multiplexing received signal from a corresponding one of the plurality of receivers into a orthogonal frequency division multiplexing received signal frequency spectrum;
at least one reference frequency spectrum generator for generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
a plurality of channel frequency response calculating units, each of said channel frequency response calculating units for calculating a channel frequency response in accordance with the frequency spectrum output from a corresponding one of the plurality of transformers and the reference frequency spectrum;
a distortion compensator for compensating for a distortion of the frequency spectrum output from each of said transformers by using the corresponding channel frequency response;
a selector unit for selecting, from among the channel frequency responses from said channel frequency response calculating units applied thereto as first input signals, the first input signals having a maximum amplitude or a maximum power, said outputting, from among the distortion compensated frequency spectra output from said distortion compensated applied thereto as second input signals, the second input signal corresponding to the selected first input signal; and
a demodulator for demodulating the output signal of said selector unit into a digital signal sequence. - View Dependent Claims (9, 15, 21, 27)
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5. A receiving apparatus comprising:
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a plurality of receivers, each of said receivers for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal;
a plurality of transformers, each of said transformers for transforming the orthogonal frequency division multiplexing received signal from a corresponding one of the plurality of receivers into a orthogonal frequency division multiplexing received signal frequency spectrum;
at least one reference frequency spectrum generator for generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
a plurality of channel frequency response calculating units, each of said channel frequency response calculating units for calculating a channel frequency response in accordance with the frequency spectrum output from each of said transformers and the reference frequency spectrum;
a distortion compensator for compensating for a distortion of the frequency spectrum output from each of said transformers by using the corresponding channel frequency response;
a selector unit for selecting and outputting, from among the distortion-compensated frequency spectra output from said distortion compensator, the distortion-compensated frequency spectrum having a maximum amplitude or a maximum power; and
a demodulator for demodulating the output signal of said selector unit into a digital signal sequence. - View Dependent Claims (10, 16, 22, 28)
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6. A receiving apparatus comprising:
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a plurality of receivers, each of said receivers for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal;
a plurality of transformers, each of said transformers for transforming the orthogonal frequency division multiplexing received signal from a corresponding one of the plurality of receivers into a orthogonal frequency division multiplexing received signal frequency spectrum;
at least one reference frequency spectrum generator for generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
a plurality of channel frequency response calculating units, each of said channel frequency response calculating units for calculating a channel frequency response in accordance with the frequency spectrum output from each of said transformers and the reference frequency spectrum;
a selector unit for selecting, in a case where the frequency spectra output from said transformers are determined as first input signals and where the channel frequency responses calculated by said channel frequency response calculating units are determined as second input signals, the first input signal having a maximum amplitude or a maximum power and the second input signal corresponding to the selected first input signal, said selector unit for outputting the selected first input signal and the selected second input signal as a first output signal and a second output signal, respectively;
a distortion compensator for compensating for a distortion of the first output signal of said selector unit by using the second output signal of said selector unit; and
a demodulator for demodulating the output signal of said distortion compensator into a digital signal sequence. - View Dependent Claims (11, 17, 23, 29)
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7. A receiving apparatus comprising:
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a plurality of receivers, each of said receivers for receiving an orthogonal frequency division multiplexing signal and outputting an orthogonal frequency division multiplexing received signal;
a plurality of transformers, each of said transformers for transforming the orthogonal frequency division multiplexing received signal from a corresponding one of the plurality of receivers into a orthogonal frequency division multiplexing received signal frequency spectrum;
at least one reference frequency spectrum generator for generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
a plurality of channel frequency response calculating units, each of said channel frequency response calculating units for calculating a channel frequency response in accordance with the frequency spectrum output from each of said transformers and the reference frequency spectrum;
a selector unit for selecting, in a case where the channel frequency responses calculated by said channel frequency response calculating units are determined as first input signals and where the frequency spectra output from said transformers are determined as second input signals, the first input signal having a maximum amplitude or a maximum power and the second input signal corresponding to the selected first input signal, said selector unit for outputting the selected first input signal and the selected second input signal as a first output signal and a second output signal, respectively;
a distortion compensator for compensating for a distortion of the second output signal of said selector unit by using the first output signal of said selector unit; and
a demodulator for demodulating the output signal of said distortion compensator into a digital signal sequence. - View Dependent Claims (12, 18, 24, 30)
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31. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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providing a plurality of diversity branches, each of said diversity branches including a receiver for receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal, a transformer for transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum and outputting the orthogonal frequency division multiplexing received signal frequency spectrum, and a channel frequency response calculating unit for calculating a channel frequency response in accordance with the orthogonal frequency division multiplexing received signal frequency spectrum and a reference frequency spectrum; and
selecting the diversity branch that has generated the orthogonal frequency division multiplexing received signal frequency spectrum having a maximum amplitude or a maximum power.
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32. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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providing a plurality of diversity branches, each of said diversity branches including a receiver for receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal, a transformer for transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum and outputting the orthogonal frequency division multiplexing received signal frequency spectrum, and a channel frequency response calculating unit for calculating a channel frequency response in accordance with the orthogonal frequency division multiplexing received signal frequency spectrum and a reference frequency spectrum; and
selecting the diversity branch that has generated the channel frequency response having a maximum amplitude or a maximum power.
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33. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal;
transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum;
generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
calculating a channel frequency response in accordance with the frequency spectrum and the reference frequency spectrum;
compensating for a distortion of the frequency spectrum by using the corresponding channel frequency response;
selecting and outputting, in a case where the frequency spectra are determined as first input signals and where the distortion-compensated frequency spectra are determined as second input signals, the second input signal corresponding to the first input signal having a maximum amplitude or a maximum power; and
demodulating the output signal of said selecting step into a digital signal sequence.
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34. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal;
transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum;
generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
calculating a channel frequency response in accordance with the frequency spectrum and the reference frequency spectrum;
compensating for a distortion of the frequency spectrum by using the corresponding channel frequency response;
selecting and outputting, in a case where the channel frequency responses are determined as first input signals and where the distortion-compensated frequency spectra are determined as second input signals, the second input signal corresponding to the first input signal having a maximum amplitude and/or a maximum power; and
demodulating the output signal of said selecting step into a digital signal sequence.
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35. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal;
transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum;
generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
calculating a channel frequency response in accordance with the frequency spectrum and the reference frequency spectrum;
compensating for a distortion of the frequency spectrum by using the corresponding channel frequency response;
selecting and outputting, among the distortion-compensated frequency spectra, the distortion-compensated frequency spectrum having a maximum amplitude or a maximum power; and
demodulating the output signal of said selecting step into a digital signal sequence.
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36. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal;
transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum;
generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
calculating a channel frequency response in accordance with the frequency spectrum and the reference frequency spectrum;
selecting, in a case where the frequency spectra are determined as first input signals and where the channel frequency responses are determined as second input signals, the first input signal having a maximum amplitude or a maximum power and the second input signal corresponding to the selected first input signal, and outputting the selected first input signal and the selected second input signal as a first output signal and a second output signal, respectively;
compensating for a distortion of the first output signal by using the second output signal; and
demodulating the output signal of said compensating step into a digital signal sequence.
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37. A method for receiving a diversity signal for use in a radio communication system that uses an orthogonal frequency division multiplexing technique, said method comprising the steps of:
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receiving an orthogonal frequency division multiplexing signal via an antenna and outputting the orthogonal frequency division multiplexing received signal;
transforming the orthogonal frequency division multiplexing received signal into a frequency spectrum;
generating a reference frequency spectrum relative to the orthogonal frequency division multiplexing received signal;
calculating a channel frequency response in accordance with the frequency spectrum and the reference frequency spectrum;
selecting, in a case where the channel frequency responses are determined as first input signals and where the frequency spectra are determined as second input signals, the first input signal having a maximum amplitude or a maximum power and the second input signal corresponding to the selected first input signal, and outputting the selected first input signal and the selected second input signal as a first output signal and a second output signal, respectively;
compensating for a distortion of the second output signal by using the first output signal; and
demodulating the output signal of said compensating step into a digital signal sequence.
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Specification