Adaptive antenna beamforming

• US 8,040,278 B2
• Filed: 06/30/2008
• Issued: 10/18/2011
• Est. Priority Date: 11/09/2007
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Maltsev, Alexander, Khoryaev, Alexey, Maslennikov, Roman
• Primary Examiner(s): Tarcza; Thomas
• Assistant Examiner(s): VIGUSHIN, JOHN B
• Application Number:
  US12/215,842
• Publication Number:
  US 20090121936A1
• Time in Patent Office: 1,205 Days
• Field of Search: 342/377, 342/378, 455/63.4, 455/562.1
• US Class Current: 342/378
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Abstract

Adaptive antenna beamforming may involve a maximum signal-to-noise ratio beamforming method, a correlation matrix based beamforming method, or a maximum ray beamforming method. The adaptive antenna beamforming may be used in a millimeter-wave wireless personal area network in one embodiment.

Claims

1. A method comprising:

beamforming by calculating antenna weight vectors to maximize a total signal to noise ratio;

calculating a transmit antenna weight vector to maximize the eigen value of a received signal correlation matrix, where the received signal correlation matrix is calculated by averaging of per subcarrier received signal correlation matrices over all active subcarriers and the receive antenna weight vector is calculated as an eigen vector corresponding to the largest eigen value of the averaged correlation matrix;

calculating the averaged correlation matrix over less than all the active subcarriers and then maximizing its largest eigen value by selecting a transmit antenna weight vector and selecting a receive antenna weight as an eigen vector corresponding to the largest eigen value of this correlation matrix; and

applying the antenna weight vectors to at least one of a receiving or transmitting antenna system.

2. The method of claim 1 including using beamforming in a millimeter-wave wireless personal area network.

3. The method of claim 1 including using as said antenna system one of a phased antenna array, a sectorized antenna, or a directional antenna.

4. The method of claim 1 including using beamforming training to estimate channel state information.

5. The method of claim 1 including applying the calculated weight vectors to the receiving antenna system.

6. The method of claim 5 including transmitting the calculated transmit antenna weight vectors to a transmit station.

7. The method of claim 1 including calculating said antenna weight vectors over the full channel bandwidth.

8. The method of claim 1 including calculating said weight vectors in the frequency domain.

9. The method of claim 1 including calculating said weight vectors in the time domain.

10. The method of claim 1 including calculating a receive antenna weight vector to maximize an eigen value of a transmitted signal correlation matrix, where the transmitted signal correlation matrix is calculated by averaging of the per subcarrier transmitted signal correlation matrices over all active subcarriers and a transmit antenna weight vector is calculated as an eigen vector corresponding to the largest eigen value of this correlation matrix.

11. The method of claim 10 including calculating the averaged correlation matrix over less than all active subcarriers and then maximizing its largest eigen value by selecting the receive antenna weight vector and selecting the transmit antenna weight vector as an eigen vector corresponding to the largest eigen value of this correlation matrix.

12. The method of claim 11 wherein calculating the averaged correlation matrix is done in the time domain by averaging over correlation matrices for different delay indices rather than in the frequency domain by averaging over the active subcarriers indices.

13. A wireless communication apparatus comprising:

a processor to determine a correlation matrix by averaging over a number of subcarriers, the multiplication of Hermitian transpose channel transfer matrix by the channel transfer matrix, said processor to determine an antenna weight vector as an eigen vector having the largest eigen value of the matrix, said processor to determine both a receive and a transmit signal correlation matrix and selecting a transmit antenna weight vector as an eigen vector corresponding to the largest eigen value of the transmit correlation matrix and selecting a receive antenna weight vector as the eigen vector corresponding to the largest eigen value of the receive correlation matrix; and

an adjustable antenna system coupled to said processor.

14. The apparatus of claim 13 including determining said correlation matrix in the frequency domain.

15. The apparatus of claim 13 including determining the correlation matrix in the time domain.

16. A method comprising:

beamforming by finding a channel matrix impulse response sample that corresponds to a most powerful ray;

using singular-value-decomposition of the channel matrix sample to find the singular-value-decomposition vectors corresponding to a maximum singular value and selecting transmit and receive antenna weight vectors as singular value decomposition vectors corresponding to the maximum singular value; and

determining the channel matrix impulse response sample using the Frobenius norm and selecting channel matrix impulse response sample with the maximum Frobenius norm.

17. The method of claim 16 including determining the channel matrix impulse response by comparing maximum singular values of channel matrix impulse response samples and selecting a sample corresponding to the largest singular value.

18. The method of claim 16 including determining the channel matrix impulse response sample using maximum element criteria by comparing the maximum absolute values of single element of each channel matrix impulse response sample and selecting channel matrix impulse response sample with the maximum value of the single element.

19. A method comprising:

beamforming by finding a channel matrix impulse response sample that corresponds to a most powerful ray;

using singular-value-decomposition of the channel matrix sample to find the singular-value-decomposition vectors corresponding to a maximum singular value and selecting transmit and receive antenna weight vectors as singular value decomposition vectors corresponding to the maximum singular value; and

determining the channel matrix impulse response sample using maximum element criteria by comparing the maximum absolute values of single element of each channel matrix impulse response sample and selecting channel matrix impulse response sample with the maximum value of the single element.

20. A method comprising:

beamforming by calculating antenna weight vectors to maximize a total signal to noise ratio;

calculating a receive antenna weight vector to maximize an eigen value of a transmitted signal correlation matrix, where the transmitted signal correlation matrix is calculated by averaging of the per subcarrier transmitted signal correlation matrices over all active subcarriers and a transmit antenna weight vector is calculated as an eigen vector corresponding to the largest eigen value of this correlation matrix;

calculating the averaged correlation matrix over less than all active subcarriers and then maximizing its largest eigen value by selecting the receive antenna weight vector and selecting the transmit antenna weight vector as an eigen vector corresponding to the largest eigen value of this correlation matrix; and

applying the antenna weight vectors to at least one of a receiving or transmitting antenna system.

21. The method of claim 20 wherein calculating the averaged correlation matrix is done in the time domain by averaging over correlation matrices for different delay indices rather than in the frequency domain by averaging over the active subcarriers indices.