Radio communication apparatus capable of switching modulation schemes
View Patent ↗A transmitting apparatus includes a modulation signal generating section that generates a modulation signal by modulating transmission data using one of a plurality of modulation schemes. The plurality of modulation schemes include a first modulation scheme, a second modulation scheme, and a third modulation scheme, where the first modulation scheme has maximum m-ary modulation value, the second modulation scheme has a lower m-ary modulation value than the first modulation scheme, and the third modulation scheme has a lower m-ary modulation value than the second modulation scheme. The transmitting apparatus also includes a pilot signal generating section that generates a pilot signal having one of a plurality of amplitudes, the pilot signal having a lower amplitude than a maximum amplitude of the first modulation scheme. The transmitting apparatus further includes a selection section that selects the modulation signal or the pilot signal according to a frame timing signal and generates a transmission quadrature baseband signal, a radio section that converts the transmission quadrature baseband signal to a radio signal, an amplifying section that amplifies the radio signal, and an antenna section that transmits the amplified radio signal.
1. A transmitting apparatus, comprising:
a modulation signal generating section that generates a modulation signal by modulating transmission data using one of a plurality of modulation schemes, the plurality of modulation schemes including a first modulation scheme, a second modulation scheme, and a third modulation scheme, the first modulation scheme having a higher m-ary modulation value than the second modulation scheme and the third modulation scheme, the second modulation scheme having a lower m-ary modulation value than the first modulation scheme, and the third modulation scheme having a lower m-ary modulation value than the second modulation scheme;
a pilot signal generating section that generates a pilot signal having one of a plurality of amplitudes, the pilot signal having a lower amplitude than a maximum amplitude of the first modulation scheme in an in-phase-quadrature plane;
a selection section that selects the modulation signal or the pilot signal according to a frame timing signal and generates a transmission quadrature baseband signal;
a radio section that converts the transmission quadrature baseband signal to a radio signal;
an amplifying section that amplifies the radio signal; and
an antenna section that transmits the amplified radio signal.
2. The transmitting apparatus according to claim 1 ,
wherein the amplitude of the pilot signal is determined according to the modulation scheme used in the modulation signal generating section.
3. The transmitting apparatus according to claim 1 ,
wherein the amplitude of the pilot signal is determined according to a bit error rate in a receiving apparatus receiving the amplified radio signal.
4. A receiving apparatus, comprising:
an antenna that receives a radio signal;
an estimation section which estimates transmission path distortion using a pilot signal included in the radio signal and outputs a distortion estimation signal; and
a demodulation section that corrects the distortion of the radio signal using the distortion estimation signal and demodulates transmission data, wherein:
the radio signal includes a modulation signal generated by modulating the transmission data using one of a plurality of modulation schemes and a pilot signal;
the plurality of modulation schemes include a first modulation scheme, a second modulation scheme, and a third modulation scheme;
the first modulation scheme has a higher m-ary modulation value than the second modulation scheme, and the third modulation scheme;
the second modulation scheme has a lower m-ary modulation value than the first modulation scheme;
the third modulation scheme has a lower m-ary modulation value than the second modulation scheme; and
an amplitude of the pilot signal is smaller than a maximum amplitude of the first modulation scheme in an in-phase-quadrature plane.