Wireless transmission method and apparatus

1. A wireless transmission method comprising:

performing feedback loop processing including subtracting a feedback data signal obtained by multiplying a first feedback processing data signal by a gain from an input data signal to generate a second feedback processing data signal;

performing beam forming processing with respect to both the second feedback processing data signal and at least one pilot signal for channel estimation to generate a beam-formed signal; and

transmitting the beam-formed signal by a plurality of antennas.

2. A wireless transmission apparatus comprising:

a feedback loop configured to perform feedback loop processing including subtracting a feedback data signal obtained by multiplying a first feedback processing data signal by a gain from an input data signal to generate a second feedback processing data signal;

a beam former configured to perform beam forming processing with respect to both the second feedback processing data signal and at least one pilot signal for channel estimation to generate a beam-formed signal; and

a transmission unit configured to transmit the beam-formed signal.

3. The apparatus according to claim 2 , wherein the transmission unit is configured to transmit the beam-formed signal by using a plurality of antennas.

4. The apparatus according to claim 2 , wherein the feedback loop further includes a calculation unit configured to perform calculation of reducing an increase in transmission power caused due to the feedback loop processing with respect to the second feedback processing data signal.

5. The apparatus according to claim 4 , wherein the calculation includes modulo arithmetic.

6. The apparatus according to claim 2 , wherein the pilot signal includes a first pilot signal for a first wireless receiver of a first user and a second pilot signal for a second wireless receiver of a second user, and the first pilot signal and the second pilot signal are orthogonal to each other.

7. The apparatus according to claim 6 , wherein the first pilot signal and the second pilot signal are orthogonal to each other in a time direction.

8. The apparatus according to claim 6 , wherein the first pilot signal and the second pilot signal are orthogonal to each other in a frequency direction.

9. A wireless transmission method comprising:

performing first feedback loop processing including subtracting a feedback data signal obtained by multiplying a first feedback processing data signal by a first gain from an input data signal to generate a second feedback processing data signal;

selecting one pilot signal with which transmission power becomes minimum from a plurality of prepared pilot signals for channel estimation;

performing second feedback loop processing including subtracting a feedback pilot signal obtained by multiplying a first feedback processing pilot signal by a second gain from the one pilot signal to generate a second feedback processing pilot signal;

performing beam forming processing with respect to the second feedback processing data signal and the second feedback processing pilot signal to generate a first beam-formed signal and a second beam-formed signal, respectively;

calculating the transmission power from one of the second feedback processing pilot signal and the second beam-formed signal; and

transmitting the first beam-formed signal and the second beam-formed signal by using a plurality of antennas.

10. A wireless transmission apparatus comprising:

a first feedback loop configured to perform first feedback loop processing including subtracting a first feedback data signal obtained by multiplying a data signal by a first gain from an input data signal to generate a second feedback processing data signal;

a selection unit configured to select one pilot signal with which transmission power becomes minimum from a plurality of prepared pilot signals for channel estimation;

a second feedback loop configured to perform second feedback loop processing including subtracting a feedback pilot signal obtained by multiplying a first feedback processing pilot signal by a second gain from the one pilot signal to generate a second feedback processing pilot signal;

a beam former configured to perform beam forming processing with respect to the second feedback processing data signal and the second feedback processing pilot signal to generate a beam-formed data signal and a beam-formed pilot signal, respectively;

a power calculation unit configured to calculate the transmission power from one of the second feedback processing pilot signal and the beam-formed pilot signal; and

a transmission unit configured to transmit the beam-formed data signal and the beam-formed pilot signal.

11. The apparatus according to claim 10 , wherein the transmission unit is configured to transmit the beam-formed data signal and the beam-formed pilot signal by using a plurality of antennas.

12. The apparatus according to claim 10 , further comprising:

a calculator configured to perform multiplication or division of the one selected pilot signal and the input data signal and provide the input data signal after multiplication or division to the first feedback loop.

13. The apparatus according to claim 10 , wherein the first feedback loop further includes a calculation unit configured to perform calculation for reducing an increase in transmission power caused due to the first feedback loop processing with respect to the second feedback processing data signal.

14. The apparatus according to claim 10 , wherein the first feedback loop includes a first calculation unit configured to perform calculation for reducing an increase in transmission power caused due to the first feedback loop processing with respect to the second feedback processing data signal,

the second feedback loop includes a second calculation unit configured to perform calculation for reducing an increase in transmission power caused due to the second feedback loop processing with respect to the second feedback processing pilot signal, and

the apparatus further comprises a notification unit configured to notify information indicative of contents of the second calculation.