METHOD AND DEVICE FOR TRANSMITTING SIGNAL

• US 20140307664A1
• Filed: 06/05/2014
• Published: 10/16/2014
• Est. Priority Date: 12/05/2011
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wang, Yi, CHEN, Zhi, Zeng, Junjie, Li, Lingxiang
• Granted Patent: US 9,484,999 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0865 Independent weighting, i.e. weights based on own antenna reception parameters

Abstract

Embodiments of the present invention provide a method and device for transmitting signal. The method includes: obtaining a downlink beamforming matrix; and using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal. In the embodiments of the present invention, the conjugate transposed matrix of the downlink beamforming matrix may be used as the uplink beamforming matrix for processing uplink signal, which can simplify design of the uplink beamforming matrix and thereby reduce complexity of the system.

Claims

1. A method for transmitting signal, comprising:

obtaining a downlink beamforming matrix; and

using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal.

2. The method according to claim 1, wherein:

the obtaining a downlink beamforming matrix comprises;

obtaining, by a first communication device, a downlink transmit beamforming matrix based on a signal to leakage plus noise ratio at a second communication device; and

the using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal comprises;

using, by the first communication device, a conjugate transposed matrix of the downlink transmit beamforming matrix as an uplink receive beamforming matrix for processing uplink signal received from the second communication device.

3. The method according to claim 2, wherein the obtaining, by a first communication device, a downlink transmit beamforming matrix based on a signal to leakage plus noise ratio at a second communication device comprises:

obtaining, by the first communication device according to a covariance matrix of an additive white Gaussian noise vector at the second communication device and a channel matrix from the first communication device to the second communication device, a downlink transmit beamforming matrix that maximizes the signal to leakage plus noise ratio at the second communication device.

4. The method according to claim 3, wherein the obtaining a downlink transmit beamforming matrix that maximizes the signal to leakage plus noise ratio at the second communication device comprises:

obtaining, by the first communication device, the downlink transmit beamforming matrix through a following formula;

5. The method according to claim 4, wherein:

when d=1, the downlink transmit beamforming matrix is an eigenvector corresponding to a maximum generalized eigenvalue of a matrix pair

6. The method according to claim 1, wherein:

the obtaining a downlink beamforming matrix comprises;

obtaining, by a second communication device, a downlink receive beamforming matrix based on a signal to interference plus noise ratio at the second communication device; and

the using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal comprises;

using, by the second communication device, a conjugate transposed matrix of the downlink receive beamforming matrix as an uplink transmit beamforming matrix for processing uplink signal sent to a first communication device.

7. The method according to claim 6, wherein the obtaining, by a second communication device, a downlink receive beamforming matrix based on a signal to interference plus noise ratio at the second communication device comprises:

obtaining, by the second communication device according to an interference plus noise covariance matrix at the second communication device and an equivalent channel matrix from the first communication device to the second communication device, a downlink receive beamforming matrix that maximizes the signal to interference plus noise ratio at the second communication device.

8. The method according to claim 7, wherein the obtaining a downlink receive beamforming matrix that maximizes the signal to interference plus noise ratio at the second communication device comprises:

obtaining, by the second communication device, the downlink receive beamforming matrix through a following formula;

9. The method according to claim 2, wherein the using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal comprises:

in the case of duality of a transceiver filter of the first communication device and duality of a transceiver filter of the second communication device, using the conjugate transposed matrix of the downlink beamforming matrix as the uplink beamforming matrix for processing uplink signal.

10. The method according to claim 2, wherein the first communication device is a macro base station, and the second communication device is a relay station, a micro base station, or a user terminal.

11. A device for transmitting signal, comprising:

an obtaining module, configured to obtain a downlink transmit beamforming matrix; and

a processing module, configured to use a conjugate transposed matrix of the downlink transmit beamforming matrix as an uplink receive beamforming matrix for processing uplink signal.

12. The device according to claim 11, wherein:

the device is a first communication device;

the obtaining module is configured to obtain the downlink transmit beamforming matrix based on a signal to leakage plus noise ratio at a second communication device; and

the processing module is configured to use the conjugate transposed matrix of the downlink transmit beamforming matrix as the uplink receive beamforming matrix for processing uplink signal received from the second communication device.

13. The device according to claim 12, wherein:

the obtaining module is configured to obtain, according to a covariance matrix of an additive white Gaussian noise vector at the second communication device and a channel matrix from the first communication device to the second communication device, a downlink transmit beamforming matrix that maximizes the signal to leakage plus noise ratio at the second communication device.

14. The device according to claim 13, wherein the obtaining module is configured to obtain the downlink transmit beamforming matrix through a following formula:

15. The device according to claim 14, wherein:

when d=1, the downlink transmit beamforming matrix is an eigenvector corresponding to a maximum generalized eigenvalue of a matrix pair

16. The device according to claim 12, wherein the processing module is configured to:

in the case of duality of a transceiver filter of the first communication device and duality of a transceiver filter of the second communication device, use a conjugate transposed matrix of a downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal.

17. The device according to claim 12, wherein the first communication device is a macro base station, and the second communication device is a relay station, a micro base station, or a user terminal.

18. A device for transmitting signal, comprising:

an obtaining module, configured to obtain a downlink receive beamforming matrix; and

a processing module, configured to use a conjugate transposed matrix of the downlink receive beamforming matrix as an uplink transmit beamforming matrix for processing uplink signal.

19. The device according to claim 18, wherein:

the device is a second communication device;

the obtaining module is configured to obtain the downlink receive beamforming matrix based on a signal to interference plus noise ratio at the second communication device; and

the processing module uses the conjugate transposed matrix of the downlink receive beamforming matrix as the uplink transmit beamforming matrix for processing uplink signal sent to a first communication device.

20. The device according to claim 19, wherein:

the obtaining module is configured to obtain, according to an interference plus noise covariance matrix at the second communication device and an equivalent channel matrix from the first communication device to the second communication device, a downlink receive beamforming matrix that maximizes the signal to interference plus noise ratio at the second communication device.

21. The device according to claim 20, wherein the obtaining module is configured to obtain the downlink receive beamforming matrix through a following formula:

22. The device according to claim 19, wherein the processing module is configured to:

in the case of duality of a transceiver filter of the first communication device and duality of a transceiver filter of the second communication device, use a conjugate transposed matrix of a downlink beamforming matrix as an uplink beamforming matrix for processing uplink signal.

23. The device according to claim 19, wherein the first communication device is a macro base station, and the second communication device is a relay station, a micro base station, or a user terminal.