Beamforming to a Subset of Receive Antennas in a Wireless MIMO Communication System

• US 20100322336A1
• Filed: 08/30/2010
• Published: 12/23/2010
• Est. Priority Date: 05/02/2006
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Hui-Ling Lou, Rohit U. Nabar
• Inventors: Nabar, Rohit U., Lou, Hui-Ling
• Granted Patent: US 8,761,287 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0473 taking constraints in layer or codeword to antenna mapping into account
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas

Abstract

In a method for controlling transmission of an information signal to a multiplicity of receive antennas associated with one or more receivers a steering matrix is developed using a subset of receive antennas, wherein the subset of receive antennas includes less than all of the multiplicity of receive antennas. Transmission of the information signal via a plurality of transmit antennas is controlled using the steering matrix.

Claims

1. A method for controlling transmission of an information signal to a multiplicity of receive antennas associated with one or more receivers, the method comprising:

developing a steering matrix using a subset of receive antennas, wherein the subset of receive antennas includes less than all of the multiplicity of receive antennas; and

controlling the transmission of the information signal via a plurality of transmit antennas using the steering matrix.

2. The method of claim 1, wherein developing the steering matrix includes computing the steering matrix at a transmitter that transmits the information signal via the plurality of transmit antennas.

3. The method of claim 1, wherein developing the steering matrix includes:

computing the steering matrix at one of the one or more receivers; and

transmitting the steering matrix from the one receiver to a transmitter that transmits the information signal via the plurality of transmit antennas,

wherein the transmitter is configured to transmit the information signal via the plurality of transmit antennas using the steering matrix.

4. The method of claim 1, wherein developing the steering matrix includes at least one of i) randomly selecting the subset of receive antennas and ii) selecting the subset of receive antennas based on an optimality criterion.

5. The method of claim 4, wherein selecting the subset of receive antennas based on the optimality criterion includes:

developing two or more test steering matrixes using different subsets of receive antennas;

transmitting a plurality of test signals by transmitting a respective test signal to a receiver using each of the two or more test steering matrixes;

determining a quality factor associated with each of the plurality of test signals to define a plurality of determined quality factors; and

selecting one of the different subsets of receive antennas as the subset of receive antennas based on the plurality of determined quality factors.

6. The method of claim 1, wherein:

a number of receive antennas are used in the subset of receive antennas; and

developing the steering matrix includes at least one of i) randomly selecting the number of receive antennas and ii) selecting the number of receive antennas based on an optimality criterion.

7. The method of claim 1, further comprising modulating the information signal.

8. An apparatus for use in transmitting an information signal to a plurality of receive antennas associated with one or more receivers, the apparatus comprising:

a beamforming network coupled to a multiplicity of transmit antennas; and

a controller coupled to the beamforming network, the controller to control the beamforming network using a steering matrix;

wherein a steering matrix calculation unit determines the steering matrix using a subset of receive antennas, the subset of receive antennas including less than all of the plurality of receive antennas.

9. The apparatus of claim 8, wherein the steering matrix calculation unit is disposed within one of the one or more receivers.

10. The apparatus of claim 8, further comprising the matrix calculation unit.

11. The apparatus of claim 8, wherein the steering matrix calculation unit is configured to determine the steering matrix using at least one of i) transmit-MRC (maximum ratio combining) and ii) singular value decomposition (SVD).

12. The apparatus of claim 8, wherein the steering matrix calculation unit is configured to at least one of i) select the subset of receive antennas randomly and ii) select the subset of receive antennas based on an optimality criterion.

13. The apparatus of claim 8, wherein:

a plurality of test signals are transmitted using a plurality of respective test steering matrixes, wherein each test steering matrix corresponds to a different subset of receive antennas; and

the steering matrix calculation unit is configured to (i) determine a quality factor associated with each of the plurality of test signals to define a plurality of determined quality factors and (ii) select one of the different subsets of receive antennas as the subset of receive antennas based on the plurality of determined quality factors.

14. The apparatus of claim 13, wherein:

a number of receive antennas are used in the subset of receive antennas; and

the steering matrix calculation unit is configured to select the number of receive antennas based on an optimality criterion.

15. The apparatus of claim 8, wherein the steering matrix calculation unit is configured to develop the steering matrix base at least in art on channel state information associated with a transmission channel between a wireless transmitter and a receiver.

16. The apparatus of claim 8, further comprising a signal modulator configured to modulate the information signal.

17. An apparatus for use in transmitting an information signal from a plurality of transmit antennas to a plurality of receive antennas associated with one or more receivers, the apparatus comprising:

a steering matrix calculation unit configured to determine a steering matrix using a subset of receive antennas, the subset of receive antennas including less than all of the plurality of receive antennas,

wherein a beamforming network coupled to the multiplicity of transmit antennas is controlled according to the steering matrix.

18. The apparatus of claim 17, wherein the steering matrix calculation unit is configured to determine the steering matrix using at least one of i) transmit-MRC (maximum ratio combining) and ii) singular value decomposition (SVD).

19. The apparatus of claim 17, wherein the steering matrix calculation unit is configured to at least one of i) select the subset of receive antennas randomly and ii) select the subset of receive antennas based on an optimality criterion.

20. The apparatus of claim 17, wherein:

a plurality of test signals are transmitted using a plurality of respective test steering matrixes, wherein each test steering matrix corresponds to a different subset of receive antennas; and

the steering matrix calculation unit is configured to (i) determine a quality factor associated with each of the plurality of test signals to define a plurality of determined quality factors, and (ii) select one of the different subsets of receive antennas as the subset of receiver antennas based on the plurality of determined quality factors.