Radio transmission device, radio reception device, radio transmission method, and radio reception method
Disclosed is a radio transmission device for lightening the waveform distortion of a received signal in a single-carrier transmission irrespective of a fading state. In this device, an FFT unit ( 103 ) converts a modulation signal outputted from a modulation unit ( 102 ), into a signal of a frequency range, and a repetition unit ( 104 ) repeats the frequency range signal outputted from the FFT unit ( 103 ), and arranges a plurality of frequency range signals adjacent to each other on a frequency axis. A tooth-shaped waveform forming unit ( 105 ) shapes the waveform of the frequency range signals outputted from the repetition unit ( 104 ), into a tooth-shaped waveform, and an IFFT unit ( 106 ) converts the frequency range signal outputted from the tooth-shaped waveform forming unit ( 105 ), into a signal of a time range.
1. A wireless transmitting apparatus comprising:
a converting section that converts a time domain signal into a frequency domain signal;
a repetition section that performs repetition, in the frequency domain, of the frequency domain signal converted by the converting section to generate a repetition signal which contains the repetition of the frequency domain signal;
an inverting section that inverts the repetition signal into an inverted time domain signal; and
a transmitting section that transmits the inverted time domain signal inverted by the inverting section.
2. The wireless transmitting apparatus according to claim 1 , wherein the repetition section maps a plurality of the frequency domain signals neighboring each other in the frequency domain.
3. The wireless transmitting apparatus according to claim 1 , further comprising a waveform forming section that forms frequency components of the repetition signal into a combtooth waveform in which zero components are inserted in between the frequency components of the repetition signal.
4. The wireless transmitting apparatus according to claim 3 , further comprising:
a phase rotating section that applies phase rotation to a plurality of the frequency domain signals in the repetition signal; and
a frequency shift section that applies frequency shift to the plurality of phase rotated frequency domain signals in the repetition signal.
5. The wireless transmitting apparatus according to claim 4 , further comprising a multiplexing section that multiplexes the plurality of frequency domain signals subjected to the phase rotation in respectively different amounts of the phase rotation by the phase rotating section and subjected to the frequency shift in respectively different amounts of the frequency shift by the frequency shift section.
6. The wireless transmitting apparatus according to claim 4 , wherein:
the phase rotating section applies the phase rotation to the plurality of frequency domain signals in respectively different amounts of the phase rotation on a per user basis; and
the frequency shift section applies the frequency shift to the plurality of phase rotated frequency domain signals in respectively different amounts of the frequency shift on the per user basis.
7. A wireless receiving apparatus comprising:
a receiving section that receives a time domain signal generated based on a frequency domain signal which is repeated in a frequency domain, wherein a repetition signal, which contains the repetition of the frequency domain signal, is inverted;
a converting section that converts the time domain signal into the repetition signal;
a dividing section that divides the repetition signal, converted by the converting section, into a plurality of the frequency domain signals;
an equalizing section that performs frequency domain equalization on the plurality of frequency domain signals divided by the dividing section;
a combining section that combines the plurality of frequency domain signals subjected to the frequency domain equalization by the equalizing section to generate a combined frequency domain signal;
an inverting section that inverts the combined frequency domain signal into an inverted time domain signal; and
a demodulating section that demodulates the inverted time domain signal inverted by the inverting section.
8. The wireless receiving apparatus according to claim 7 , further comprising a puncturing section that, when the repetition signal has a combtooth waveform in which zero components are inserted in between frequency components of the repetition signal, punctures the inserted zero components.
9. The wireless receiving apparatus according to claim 7 , further comprising:
a frequency shift section that, when the plurality of the frequency domain signals in the repetition signal are subjected to phase rotation and frequency shift, performs another frequency shift on the plurality of the frequency domain signals in a reverse amount of shift of an amount of shift applied to the plurality of the frequency domain signals; and
a phase rotating section that performs phase rotation to the plurality of shifted frequency domain signals in a reverse amount of phase rotation of an amount of phase rotation applied to the plurality of the shifted frequency domain signals.
10. A wireless transmission method, comprising the steps of:
converting a time domain signal into a frequency domain signal;
performing repetition, in a frequency domain, of the frequency domain signal to generate a repetition signal which contains the repetition of the frequency domain signal;
inverting the repetition signal into an inverted time domain signal; and
transmitting the inverted time domain signal.
11. A wireless reception method comprising the steps of:
receiving a time domain signal generated based on a frequency domain signal which is repeated in a frequency domain, wherein a repetition signal, which contains the repetition of the frequency domain signal, is inverted;
converting the time domain signal into the repetition signal;
dividing the repetition signal into a plurality of the frequency domain signals;
performing frequency domain equalization on the plurality of frequency domain signals;
combining the plurality of frequency domain signals subjected to frequency domain equalization to generate a combined frequency domain signal;
inverting the combined frequency domain signal into an inverted time domain signal; and
demodulating the inverted time domain signal.