Method for creating beamformed multiple-input-multiple-output channels with partial nulling

1. A method for creating beamformed multiple-input-multiple-output (MIMO) channels, the method comprising:

receiving by a first wireless station a first plurality of receiving signals transmitted from a first antenna on a second wireless station;

receiving by the first wireless station a second plurality of receiving signals transmitted from a second antenna on the second wireless station;

nulling out a first predetermined percentage of the second plurality of receiving signals to generate a third plurality of receiving signals;

calculating a first beamforming weighting vector corresponding to the first antenna on the second wireless station using the first and third pluralities of receiving signals; and

creating a first beamformed MIMO channel from the first wireless station to the first antenna on the second wireless station using the first beamforming weighting vector.

2. The method of claim 1 , wherein the first plurality of receiving signals are selected from a group comprising data signals and sounding signals.

3. The method of claim 1 , wherein the second plurality of receiving signals are selected from a group comprising data signals and sounding signals.

4. The method of claim 1 , wherein the first beamforming weighting vector is a primary eigenvector of the following matrix: (α*R i +σ n 2 *I) −1 R s *W i =λ*W i , where R i is the covariance matrix calculated from the interference signals; σ n is the standard deviation of channel noises; R s is the covariance matrix calculated from the desired signals; I is the identity matrix; λ is the maximum eigenvalue; and α, a scaling factor, depicts the predetermined percentage of the interference signals that are nulled out.

5. The method of claim 1 , wherein the first predetermined percentage is determined by a plurality of applications and a plurality of operating environments.

6. The method of claim 1 , wherein the first wireless station is a base station and the second wireless station is a mobile station.

7. The method of claim 1 , wherein the first wireless station is a mobile station and the second wireless station is a base station.

8. The method of claim 1 further comprising:

nulling out a second predetermined percentage of the first plurality of receiving signals to generate a fourth plurality of receiving signals;

computing a second beamforming weighting vector corresponding to the second antenna on the second wireless station using the second and fourth pluralities of receiving signals; and

creating a second beamformed MIMO channel from the first wireless station to the second antenna on the second wireless station using the second computed beamforming weighting vector.

9. A method for creating beamformed multiple-input-multiple-output (MIMO) channels, the method comprising:

receiving by a first wireless station a first plurality of receiving signals transmitted from a first antenna on a second wireless station;

receiving by the first wireless station a second plurality of receiving signals transmitted from a second antenna on the second wireless station;

nulling out a first predetermined percentage of the second plurality of receiving signals to generate a third plurality of receiving signals;

nulling out a second predetermined percentage of the first plurality of receiving signals to generate a fourth plurality of receiving signals;

calculating a first beamforming weighting vector corresponding to the first antenna on the second wireless station using the first and third pluralities of receiving signals;

calculating a second beamforming weighting vector corresponding to the second antenna on the second wireless station using the second and fourth pluralities of receiving signals;

creating a first beamformed MIMO channel from the first wireless station to the first antenna on the second wireless station using the first beamforming weighting vector; and

creating a second beamformed MIMO channel from the first wireless station to the second antenna on the second wireless station using the second computed beamforming weighting vector.

10. The method of claim 9 , wherein the first plurality of receiving signals are selected from a group comprising data signals and sounding signals.

11. The method of claim 9 , wherein the second plurality of receiving signals are selected from a group comprising data signals and sounding signals.

12. The method of claim 9 , wherein the first or second beamforming weighting vector is a primary eigenvector of the following matrix: (α*R i +σ n 2 *I) −1 R s *W i =λ*W i , where R i is the covariance matrix calculated from the interference signals; σ n is the standard deviation of channel noises; R s is the covariance matrix calculated from the desired signals; I is the identity matrix; λ is the maximum eigenvalue; and α, a scaling factor, depicts the predetermined percentage of the interference signals that are nulled out.

13. The method of claim 9 , wherein the first or second predetermined percentage is determined by a plurality of applications and a plurality of operating environments.

14. The method of claim 9 , wherein the first wireless station is a base station and the second wireless station is a mobile station.

15. The method of claim 9 , wherein the first wireless station is a mobile station and the second wireless station is a base station.

16. A method for creating beamformed multiple-input-multiple-output (MIMO) channels, the method comprising:

receiving by a base station (BS) a first plurality of receiving signals transmitted from a first antenna on a mobile station (MS);

receiving by the BS a second plurality of receiving signals transmitted from a second antenna on the MS;

nulling out a first predetermined percentage of the second plurality of receiving signals to generate a third plurality of receiving signals;

calculating a first beamforming weighting vector corresponding to the first antenna on the MS using the first and third pluralities of receiving signals; and

creating a first beamformed MIMO channel from the BS to the first antenna on the MS using the first beamforming weighting vector.

17. The method of claim 16 , wherein the first plurality of receiving signals are selected from the group comprising data signals and sounding signals.

18. The method of claim 16 , wherein the second plurality of receiving signals are selected from the group comprising data signals and sounding signals.

19. The method of claim 16 , wherein the first beamforming weighting vector is a primary eigenvector of the following matrix: (α*R i +σ n 2 *I) −1 R s *W i =λ*W i , where R i is the covariance matrix calculated from the interference signals; σ n is the standard deviation of channel noises; R s is the covariance matrix calculated from the desired signals; I is the identity matrix; λ is the maximum eigenvalue; and α, a scaling factor, depicts the predetermined percentage of the interference signals that are nulled out.

20. The method of claim 16 further comprising:

nulling out a second predetermined percentage of the first plurality of receiving signals to generate a fourth plurality of receiving signals;

computing a second beamforming weighting vector corresponding to the second antenna on the MS using the second and fourth pluralities of receiving signals; and

creating a second beamformed MIMO channel from the BS to the second antenna on the MS using the second computed beamforming weighting vector.