Transmission signal generation apparatus, transmission signal generation method, reception signal apparatus, and reception signal method

1. A transmission apparatus comprising:

electronic circuitry to:

map a first stream of input data to first complex symbols in serial format;

convert the first complex symbols in serial format into first complex symbols in parallel format;

perform an inverse Fourier transform on the first complex symbols in parallel format to form first Orthogonal Frequency Division Multiplexed (OFDM) signals associated with multiple subcarriers;

transmit the first OFDM signals via a first antenna over the multiple subcarriers in a same frequency band over a same time period that includes a same set of time slots;

transmit first pilot information via a first antenna on a first one of a plurality of pilot subcarriers during the same set of time slots;

transmit second pilot information via a first antenna on a second one of a plurality of pilot subcarriers during the same set of time slots, the second pilot information being different from the first pilot information;

map a second stream of input data to second complex symbols in serial format;

convert the second complex symbols in serial format into second complex symbols in parallel format;

perform an inverse Fourier transform on the second complex symbols in parallel format to form second OFDM signals associated with the multiple subcarriers;

transmit the second OFDM signals via a second antenna over the multiple subcarriers in the same frequency band over the same time period that includes the same set of time slots,

transmit the first pilot information via the second antenna on the second pilot subcarrier during the same set of time slots; and

transmit the second pilot information on one of the plurality of pilot subcarriers during the same set of time slots.

2. The transmission apparatus of claim 1 , wherein the first pilot information is orthogonal to the second pilot information.

3. The transmission apparatus of claim 1 , wherein the first OFDM signals include preamble information, pilot information, and data information, and wherein the second OFDM signals include preamble information, pilot information, and data information.

4. The transmission apparatus of claim 1 , wherein the electronic circuitry is adapted to:

map a third stream of input data and pilot bits to third complex symbols in serial format;

convert the third complex symbols in serial format into third complex symbols in parallel format;

perform an inverse Fourier transform on the third complex symbols in parallel format to form third OFDM signals associated with the multiple subcarriers including the plurality of pilot symbol subcarriers; and

transmit the third OFDM signals via a third antenna over the multiple subcarriers in the same frequency band over the same time period that includes the same set of time slots.

5. The transmission apparatus of claim 1 , wherein the electronic circuitry is configured with multiple sections including one or more mapping sections, one or more converting sections, one or more inverse Fourier transform sections, and one or more transmission sections.

6. The transmission apparatus of claim 1 , wherein each of the first pilot information and the second pilot information includes plural pilot sequences having values from a set {1, −1}.

7. The transmission apparatus of claim 6 , wherein the plural pilot sequences have the same length.

8. The transmission apparatus of claim 7 , wherein the length for the plural pilot sequences is 4.

9. A Multiple Input Multiple Output (MIMO) signal reception apparatus comprising:

one or more antennas configured to receive, over an identical frequency band at an identical time period, a plurality of Orthogonal Frequency Division Multiplexed (OFDM) signals, each of the OFDM signals including plural pilot carriers carrying pilot sequences located at identical carrier positions among the OFDM radio signals, orthogonal ones of the pilot sequences being assigned to an identical carrier position among the OFDM signals, and the OFDM signals including an identical one of the pilot sequences during an identical time period, and

electronic circuitry to:

convert a received first OFDM signal to a first baseband OFDM signal;

Fourier transform the first baseband OFDM signal to first complex symbols;

demodulate the first complex symbols into a first output bit stream;

convert a received second OFDM signal to a second baseband OFDM signal;

Fourier transform the second baseband OFDM signal to second complex symbols;

and

demodulate the second complex symbols into a second output bit stream,

wherein orthogonal pilot sequences are detectable at identical time slots of pilot carriers on an identical carrier position between the received first OFDM signal and the received second OFDM signal, and an identical pilot sequence is detectable in a part of the first OFDM signal and a part of the second OFDM signal.

10. The MIMO signal reception apparatus of claim 9 , wherein the first OFDM signals include preamble information, pilot information, and data information, and wherein the second OFDM signals include preamble information, pilot information, and data information.

11. The MIMO signal reception apparatus of claim 9 , wherein each of the first pilot information and the second pilot information includes plural pilot sequences having values from a set {1, −1}.

12. The MIMO signal reception apparatus of claim 11 , wherein the plural pilot sequences have the same length.

13. The MIMO signal reception apparatus of claim 12 , wherein the length for the plural pilot sequences is 4.

14. A transmission method comprising:

mapping a first stream of input data to first complex symbols in serial format;

converting the first complex symbols in serial format into first complex symbols in parallel format;

performing an inverse Fourier transform on the first complex symbols in parallel format to form first Orthogonal Frequency Division Multiplexed (OFDM) signals associated with multiple subcarriers;

transmitting the first OFDM signals via a first antenna over the multiple subcarriers in a same frequency band over a same time period that includes a same set of time slots;

transmitting first pilot information via a first antenna on a first one of a plurality of pilot subcarriers during the same set of time slots;

transmitting second pilot information via a first antenna on a second one of a plurality of pilot subcarriers during the same set of time slots, the second pilot information being different from the first pilot information;

mapping a second stream of input data to second complex symbols in serial format;

converting the second complex symbols in serial format into second complex symbols in parallel format;

performing an inverse Fourier transform on the second complex symbols in parallel format to form second OFDM signals associated with the multiple subcarriers;

transmitting the second OFDM signals via a second antenna over the multiple subcarriers in the same frequency band over the same time period that includes the same set of time slots,

transmitting the first pilot information via the second antenna on the second pilot subcarrier during the same set of time slots; and

transmitting the second pilot information on one of the plurality of pilot subcarriers during the same set of time slots.

15. The transmission method of claim 14 , wherein the first pilot information is orthogonal to the second pilot information, and wherein the first OFDM signals include preamble information, pilot information, and data information, and wherein the second OFDM signals include preamble information, pilot information, and data information.

16. The transmission method of claim 14 , further comprising:

mapping a third stream of input data and pilot bits to third complex symbols in serial format;

converting the third complex symbols in serial format into third complex symbols in parallel format;

performing an inverse Fourier transform on the third complex symbols in parallel format to form third OFDM signals associated with the multiple subcarriers including the plurality of pilot symbol subcarriers; and

transmitting the third OFDM signals via a third antenna over the multiple subcarriers in the same frequency band over the same time period that includes the same set of time slots.

17. The transmission method of claim 14 , wherein each of the first pilot information and the second pilot information includes plural pilot sequences having values from a set {1, −1}, and wherein the plural pilot sequences have the same length.

18. A Multiple Input Multiple Output (MIMO) signal reception method comprising:

receiving via one or more antennas, over an identical frequency band at an identical time period, a plurality of Orthogonal Frequency Division Multiplexed (OFDM) signals, each of the OFDM signals including plural pilot carriers carrying pilot sequences located at identical carrier positions among the OFDM radio signals, orthogonal ones of the pilot sequences being assigned to an identical carrier position among the OFDM signals, and the OFDM signals including an identical one of the pilot sequences during an identical time period;

converting a received first OFDM signal to a first baseband OFDM signal;

Fourier transforming the first baseband OFDM signal to first complex symbols;

demodulating the first complex symbols into a first output bit stream;

converting a received second OFDM signal to a second baseband OFDM signal;

Fourier transform the second baseband OFDM signal to second complex symbols; and

demodulating the second complex symbols into a second output bit stream,

wherein orthogonal pilot sequences are detected at identical time slots of pilot carriers on an identical carrier position between the received first OFDM signal and the received second OFDM signal, and an identical pilot sequence is detected in a part of the first OFDM signal and a part of the second OFDM signal.

19. The MIMO signal reception method of claim 18 , wherein the first OFDM signals include preamble information, pilot information, and data information, and wherein the second OFDM signals include preamble information, pilot information, and data information.

20. The MIMO signal reception method of claim 18 , wherein each of the first pilot information and the second pilot information includes plural pilot sequences having values from a set {1, −}and wherein the plural pilot sequences have the same length.