Beamforming for non-collaborative, space division multiple access systems

• US 7,602,837 B2
• Filed: 10/20/2005
• Issued: 10/13/2009
• Est. Priority Date: 10/20/2005
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Mundarath, Jayakrishnan C., Kotecha, Jayesh H.
• Primary Examiner(s): Tran, Khai
• Application Number:
  US11/254,392
• Publication Number:
  US 20070092019A1
• Time in Patent Office: 1,454 Days
• Field of Search: 375/148, 375/130, 375/267, 375/347, 375/349, 375/299, 370/342, 370/203, 370/299, 455/101, 455/132
• US Class Current: 375/148
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0897 using beamforming per multi-path, e.g. to cope with different directions of arrival [DOA] at different multi-paths
• CPC Class Codes: H04L 25/0248 Eigen-space methods

Abstract

A wireless communication system noncollaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system determines subscriber station combining and weighting vectors that yield a high average signal-to-interference plus noise ratio (SINR). Each subscriber station independently transmits information to a base station that allows the base station to determine a weight vector w_i for each subscriber station using the determined combining vector of the subscriber station. The i^th combining vector corresponds to a right singular vector corresponding to a maximum singular value of a channel matrix between a base station and the i^th subscriber station. Each subscriber station transmits signals using a weight vector v_i, which corresponds to a left singular vector corresponding to a maximum singular value of a channel matrix between the i^th subscriber station and the base station. The base station uses the weight vector w_i to determine the signal transmitted by the i^th subscriber station.

Claims

1. A wireless communication method using beamforming for a noncollaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system, the method comprising:

receiving signals on k multiple antennas of a first device, wherein “

k”

is an integer greater than one (1);

during at least a first period of time, combining the signals using a combining vector v₁, wherein the combining vector v₁ corresponds to a right singular vector corresponding to a substantially maximal singular value of channel matrix H₁, wherein H₁ represents a channel between the first device and a second device;

during at least the first period of time, determining a data signal using the combining vector v₁; and

transmitting information to a second device that allows the second device to use the combining vector v₁ to design a weight vector.

2. The method of claim 1 further comprising:

transmitting a signal to the second device using a weight vector v₁, wherein the weight vector v₁ corresponds to a left singular vector corresponding to the maximal singular value of an uplink channel matrix H_i.

3. The method of claim 1 further comprising:

determining whether the combining vector v₁ or a combining vector v_A provides better signal-to-interference plus noise ratio; and

during at least a second period of time, determining the data signal using the combining vector v₁ if the combining vector v₁ provides a better signal-to-interference plus noise ratio and otherwise determining the combined signal using the combining vector v_A.

4. The method of claim 3 wherein the combining vector v_A is determined based on statistical interference and instantaneous interference.

5. The method of claim 1 further comprising:

determining the combining vector v₁ using a processor of the first device.

6. The method of claim 1 further comprising:

determining the combining vector v₁ independently of combining vectors and channel matrices of all other devices in the MIMO-SDMA system.

7. The method of claim 1 wherein y₁ is a k element reception vector for the first device, w_l^H is an N element, conjugate transpose of a signal weighting vector w₁, y₁=s₁Ĥ

₁^Hw₁+interference, z₁ represents the combined signal, and determining the data signal using the combining vector v₁ comprises;

determining a dot product of a conjugate transpose of the combining vector v₁ and the reception vector y₁ such that z₁=v₁^Hy₁ and “

z₁”

represents the data signal.

8. The method of claim 1 wherein the information transmitted to the second device allows the second device to use the combining vector v₁ to generate a weight vector for transmission of signals from the second device to the first device.

9. The method of claim 1 wherein the first device is selected from the group comprising cellular telephones, wireless equipped computer systems, and wireless personal digital assistants.

10. A subscriber station comprising:

a receiver to receive beam formed signals on k antennas of a first receiver, wherein “

k”

is an integer greater than one;

a module to combine the signals using a combining vector v₁ to determine a data signal, wherein during at least a first period of time, the combining vector v₁ corresponds to a right singular vector corresponding to a substantially maximal singular value of channel matrix H₁, wherein H₁ represents a channel between the first receiver and a base station; and

a transmitter to transmit information to a multiple antenna base station that allows the base station to use the combining vector v₁ to design a weight vector.

11. The subscriber station of claim 10 wherein the transmitter is further capable of transmitting a signal to the base station using a weight vector v₁, wherein the weight vector v₁ corresponds to a left singular vector corresponding to the maximal singular value of an uplink channel matrix H_i.

12. The subscriber station of claim 10 wherein channel matrix H₁ is an estimate of an actual channel matrix, and the coefficients of channel matrix H_i represent channel gains.

13. The subscriber station of claim 10 further comprising:

a determination module to determine whether the combining vector v₁ or a combining vector v_A provides better signal-to-interference plus noise ratio and to determine, during at least a second period of time, the data signal using the combining vector v₁ if the combining vector v₁ provides a better signal-to-interference plus noise ratio and otherwise determining the combined signal using the combining vector v_A.

14. The subscriber station of claim 13 wherein the combining vector v_A is determined based on statistical interference and instantaneous interference.

15. The subscriber station of claim 10 further comprising:

a module to determine the combining vector v₁ using a processor of the first receiver.

16. The subscriber station of claim 10 further comprising:

a module to determine the combining vector v₁ independently of combining vectors and channel matrices of all other subscriber stations.

17. The subscriber station of claim 10 wherein y₁ is a k element reception vector for the first receiver, w_l^H is an N element, conjugate transpose of a signal weighting vector w₁, y₁=s₁Ĥ

₁^Hw₁+interference, and to determine the data signal using the combining vector v₁, the module to combine the signals is further capable of;

determining a dot product of a conjugate transpose of the combining vector v₁ and the reception vector y₁ such that z₁=v₁^Hy₁, wherein “

z₁”

represents the data signal.

18. The subscriber station of claim 10 wherein the information transmitted to the base station that allows the base station to use the combining vector v₁ comprises data from which the combining vector v₁ can be derived.

19. The subscriber station of claim 10 wherein the subscriber station is selected from the group comprising cellular telephones, wireless equipped computer systems, and wireless personal digital assistants.

20. A wireless communication method using beamforming for a noncollaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system, the method comprising:

determining a weight vector v₁ corresponding to a left singular vector corresponding to a substantially maximal singular value of channel matrix H₁, wherein H₁ represents a channel between a first device and a second device;

transmitting information to the second device from the first device that allows the second device to use a combining vector v₁ corresponding to a right singular vector corresponding to a substantially maximal singular value of channel matrix H₁ to design a weight vector w₁; and

transmitting a signal to the second device using the weight vector v₁.