Radio communication apparatus and radio communication method
View Patent ↗A radio communication device capable of lightening the influence of a frequency selective fading in the wide-band transmission of a single carrier thereby to prevent deterioration of error rate characteristics. In this device, an FFT unit ( 13 ) subjects a modulated signal inputted from a modulation unit ( 12 ) to a Fourier transformation. A pilot insertion unit ( 14 ) inserts a pilot symbol into a plurality of individual frequency components ( 1 -N) of the modulated signal. Weight multiplication units ( 15 - 1, 15 - 2 ) multiply the individual frequency components ( 1 -N) and the pilot symbols inserted into the individual frequency components ( 1 -N), by weight coefficients (W 11 -W 1 N, W 21 -W 2 N) set at a weight coefficient setting unit ( 54 ). IFFT units ( 16 - 1, 16 - 2 ) subject the frequency components ( 1 -N) to an inverse Fourier transformation, thereby to convert the frequency components ( 1 -N) into time domains.
1. A radio communication apparatus comprising:
a first antenna and a second antenna;
a first conversion section that converts an input signal to a frequency domain to obtain a plurality of frequency components of the input signal;
a measuring section that measures, for each of the plurality of frequency components, a first propagation path quality of the first antenna and a second propagation path quality of the second antenna;
a weighting section that weights each of the plurality of frequency components, using a first weighting factor, to obtain a first plurality of weighted frequency components, and weights each of the plurality of frequency components, using a second weighting factor, to obtain a second plurality of weighted frequency components, the first weighting factor and the second weighting factor being set in accordance with the first propagation path quality and the second propagation path quality;
a second conversion section that converts the first plurality of weighted frequency components to a time domain to obtain a first transmit signal, and converts the second plurality of weighted frequency components to the time domain to obtain a second transmit signal; and
a transmitting section that transmits the first transmit signal and the second transmit signal from one or both of the first antenna and the second antenna.
2. The radio communication apparatus according to claim 1 , wherein the weighting section compares the first propagation path quality and the second propagation path quality, for each of the plurality of frequency components, and sets one of the first weighting factor and the second weighting factor to 1 and sets the other to 0, for each of the plurality of frequency components in, accordance with a comparison result.
3. The radio communication apparatus according to claim 2 , wherein the weighting section sets one of the first weighting factor and the second weighting factor to 1 and sets the other to 0, only for a frequency component where a difference between the first propagation path quality and the second propagation path quality is greater than or equal to a threshold value.
4. The radio communication apparatus according to claim 1 , wherein the weighting section has a plurality of combinations of the first weighting factor and the second weighting factor, and selects, from among the plurality of combinations, such a combination that received power on a signal receiving side becomes maximum, in accordance with the first propagation path quality and the second propagation path quality, to set the first weighting factor and the second weighting factor.
5. The radio communication apparatus according to claim 1 , wherein the measuring section measures, as the first propagation path quality, received power of each of a plurality of frequency components of a signal received by the first antenna, and measures, as the second propagation path quality, received power of each of a plurality of frequency components of a signal received by the second antenna.
6. The radio communication apparatus according to claim 1 , further comprising an insertion section that inserts a pilot symbol into each of the plurality of frequency components,
wherein the weighting section weights the pilot symbol using the same weighting factor as used for the plurality of frequency components.
7. The radio communication apparatus according to claim 1 , further comprising
an insertion section that inserts a signal for suppressing peak power, into a frequency component where one of the first propagation path quality and the second propagation path quality is lower than the other by a predetermined value or more, among the plurality of frequency components.
8. The radio communication apparatus according to claim 1 , wherein the transmitting section, when a peak to average power ratio is greater than or equal to a threshold value, transmits a combined signal where the first transmit signal and the second transmit signal are combined, or the input signal, from one of the first antenna and the second antenna.
9. The radio communication apparatus according to claim 8 , wherein the transmitting section transmits the combined signal from an antenna, of the first antenna and the second antenna, where a total of propagation path qualities of the plurality of frequency components is larger.
10. A radio communication base station apparatus comprising the radio communication apparatus according to claim 1 .
11. A radio communication terminal apparatus comprising the radio communication apparatus according to claim 1 .
12. A radio communication method comprising:
converting an input signal to a frequency domain to obtain a plurality of frequency components of the input signal;
measuring, for each of the plurality of frequency components, a first propagation path quality of a first antenna and a second propagation path quality of a second antenna;
weighting each of the plurality of frequency components, using a first weighting factor, to obtain a first plurality of weighted frequency components, and weighting each of the plurality of frequency components, using a second weighting factor, to obtain a second plurality of weighted frequency components, the first weighting factor and the second weighting factor being set in accordance with the first propagation path quality and the second propagation path quality;
conversion step of converting the first plurality of weighted frequency components to a time domain to obtain a first transmit signal, and converting the second plurality of weighted frequency components to the time domain to obtain a second transmit signal; and
transmitting the first transmit signal and the second transmit signal from one or both of the first antenna and the second antenna.
13. A radio communication apparatus comprising:
a first antenna and a second antenna;
a first conversion section that converts an input signal to a frequency domain to obtain a plurality of frequency components of the input signal;
a weighting section that weights the plurality of frequency components using a first weighting factor, and weights the plurality of frequency components using a second weighting factor;
a second conversion section that converts the plurality of frequency components weighted using the first weighting factor, to a time domain, to obtain a first transmit signal, and converts the plurality of frequency components weighted using the second weighting factor, to the time domain, to obtain a second transmit signal; and
a transmitting section that transmits the first transmit signal and the second transmit signal from one or both of the first antenna and the second antenna, wherein:
the transmitting section, when a peak to average power ratio is greater than or equal to a threshold value, transmits a combined signal where the first transmit signal and the second transmit signal are combined, or the input signal, from one of the first antenna and the second antenna; and
the transmitting section transmits the combined signal from an antenna, of the first antenna and the second antenna, where a total of propagation path qualities of the plurality of frequency components is larger.