Transmission and reception apparatus and method

1. A transmission apparatus comprising:

(a) a plurality of orthogonal frequency division multiplexing (OFDM)modulation signal generators configured to:

(i) generate a first OFDM modulation signal by:

inserting a first symbol for demodulation in a first plurality of subcarriers at a first time and in a second plurality of sub-carriers at a second time;

inserting a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

inserting a first data symbol in the first and second pluralities of subcarriers at a third time; and

(ii) generate a second OFDM modulation signal by:

inserting a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in the I-Q plane of zero, in the first plurality of subcarriers at the first time and in the second plurality of sub-carriers at the second time; and

inserting a second symbol for demodulation in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

inserting a second data symbol in the first and second pluralities of subcarriers at the third time; and

(b) a transmitter configured to transmit the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

2. The transmission apparatus according to claim 1 , wherein the first OFDM modulation signal and the second OFDM modulation signal are comprised of data symbols.

3. The transmission apparatus according to claim 1 , wherein the first and second symbols for demodulation are pilot symbols.

4. The transmission apparatus according to claim 1 , wherein the first and second symbols for demodulation are preambles.

5. The transmission apparatus according to claim 1 , wherein the first and second symbols for demodulation are symbols to estimate a transmission path fluctuation.

6. The transmission apparatus according to claim 1 , wherein the first and second symbols for demodulation are symbols to estimate frequency offset.

7. The transmission apparatus according to claim 1 , wherein the first and second symbols for demodulation are comprised of phase shift keying (PSK) modulation symbols.

8. A transmission method comprising:

(a) generating a first orthogonal frequency division multiplexing (OFDM) modulation signal, utilizing first OFDM modulation signal generators, by:

inserting a first symbol for demodulation in a first plurality of sub-carriers at a first time and in a second plurality of sub-carriers at a second time;

inserting a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

inserting a first data symbol in the first and second pluralities of subcarriers at a third time; and

(b) generating a second OFDM modulation signal, utilizing second OFDM modulation signal generators, by:

inserting a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in the I-Q plane of zero, in the first plurality of subcarriers at the first time and in the second plurality of sub-carriers at the second time;

inserting a second symbol for demodulation in the second plurality of subcarriers at the first time and in the first plurality of sub-carriers at the second time; and

inserting a second data symbol in the first and second pluralities of subcarriers at the third time; and

(c) transmitting the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

9. A reception apparatus comprising:

a plurality of antennas configured to receive a plurality of orthogonal frequency division multiplexing (OFDM) modulation signals;

a plurality of OFDM demodulators configured to transform the plurality of OFDM modulation signals to a plurality of reception signals using Fourier transform;

an estimator configured to output a distortion estimation signal using at least one of symbols for demodulation included in the plurality of reception signals; and

a demodulator configured to compensate a distortion of at least one of the plurality of reception signals using the distortion estimation signal and to demodulate a data symbol included in the at least one reception signal,

wherein a first OFDM modulation signal of the plurality of OFDM modulation signals includes:

a first symbol for demodulation inserted in a first plurality of sub-carriers at a first time and in a second plurality of sub-carriers at a second time;

a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, inserted in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

a first data symbol inserted in the first and second pluralities of subcarriers at a third time; and

a second OFDM modulation signal of the plurality of OFDM modulation signals includes:

a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in the I-Q plane of zero, inserted in the first plurality of sub-carriers at the first time and in the second plurality of sub-carriers at the second time;

a second symbol for demodulation inserted in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

a second data symbol inserted in the first and second pluralities of subcarriers at the third time.

10. The reception apparatus according to claim 9 , wherein the first and second symbols for demodulation are pilot symbols.

11. The reception apparatus according to claim 9 , wherein the first and second symbols for demodulation are preambles.

12. The reception apparatus according to claim 9 , wherein the first and second symbols for demodulation are symbols to estimate a transmission path fluctuation.

13. The reception apparatus according to claim 9 , wherein the first and second symbols for demodulation are symbols to estimate frequency offset.

14. The reception apparatus according to claim 9 , wherein the first and second symbols for demodulation are comprised of phase shift keying (PSK) modulation symbols.

15. A reception method comprising:

receiving a plurality of orthogonal frequency division multiplexing (OFDM) modulation signals by a plurality of antennas;

transforming the plurality of OFDM modulation signals to a plurality of reception signals using Fourier transform;

outputting a distortion estimation signal using at least one of symbols for demodulation included in the plurality of reception signals; and

compensating a distortion of at least one of the plurality of reception signals using the distortion estimation signal and demodulating a data symbol included in the at least one reception signal,

wherein a first OFDM modulation signal of the plurality of OFDM modulation signals includes:

a first symbol for demodulation inserted in a first plurality of sub-carriers at a first time and in a second plurality of sub-carriers at a second time;

a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, inserted in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

a first data symbol inserted in the first and second pluralities of subcarriers at a third time; and

a second OFDM modulation signal of the plurality of OFDM modulation signals includes:

a symbol, having both an in-phase (I) component and a quadrature-phase (Q) component in the I-Q plane of zero, inserted in the first plurality of sub-carriers at the first time and in the second plurality of sub-carriers at the second time;

a second symbol for demodulation inserted in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time; and

a second data symbol inserted in the first and second pluralities of subcarriers at the third time.