Method and device for transmitting signal

Patent metadata

Field	Value
Publication number	US-9484999-B2
Application number	US-201414297022-A
Country	US
Kind code	B2
Filing date	Jun 5, 2014
Priority date	Dec 5, 2011
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

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.

First claim

What is claimed is:

1. A method for transmitting signal, comprising:
obtaining a downlink beamforming matrix by optimizing a quantity with respect to the beamforming matrix for a channel matrix between a first communication device and a second communication device; and
using a conjugate transposed matrix of the downlink beamforming matrix as an uplink beamforming matrix for processing an uplink signal,
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.

2. The method according to claim 1 , wherein: the obtaining a downlink beamforming matrix comprises:
obtaining, by the first communication device and as the downlink beamforming matrix, a downlink transmit beamforming matrix based on the optimized quantity being a signal to leakage 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 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 the first communication device, the downlink transmit beamforming matrix based on a signal to leakage plus noise ratio at the 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 the channel matrix from the first communication device to the second communication device, the 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 the 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:

argmax

W
→

i

∈

C

M
×
d

⁢

⁢
SLNR

=

argmax

W
→

i

∈

C

M
×
d

⁢

Tr
⁡

(

W
→

i
H

⁢

H
→

i
H

⁢

H
→

i

⁢

W
→

i

)

Tr
[

W
→

i
H

(

N
⁢

⁢

σ
i
2

⁢
I

+

∑

j
≠
i

⁢

⁢

H
→

j
H

⁢

H
→

j

)

⁢

W
→

i

]

;

wherein: i is a serial number of the second communication devise, and the SLNR is the signal to leakage plus noise ratio at the second communication device; {right arrow over (W)} i is a downlink transmit beamforming matrix to be solved, and {right arrow over (W)} i εC M×d ; {right arrow over (H)} i is a channel matrix from the first communication device to a second communication de

Assignees

• Huawei Tech Co Ltd

Inventors

• Chen Zhi
• Zeng Junjie
• Li Lingxiang
• Wang Yi

Classifications

• H04B7/0456

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04B7/0617 Primary

  for beam forming · CPC title

• H04B7/0865

  Independent weighting, i.e. weights based on own antenna reception parameters · CPC title