Beamforming method, apparatus for polarized antenna array and radio communication device and system thereof

Patent metadata

Field	Value
Publication number	US-9685702-B2
Application number	US-201013991990-A
Country	US
Kind code	B2
Filing date	Dec 17, 2010
Priority date	Dec 17, 2010
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

The invention discloses a beamforming method for polarized antenna array consisting of a plurality of antenna elements, applied to single layer beamforming or dual layer beamforming, which includes the steps: determining ( 201 ) first beamforming weights for phase compensation among the antenna elements within each polarization direction; determining ( 202 ) second beamforming weights for phase compensation between equivalent channels of two polarization directions; and calculating ( 203 ) hybrid beamforming weights as product of the first beamforming weights and the second beamforming weights. A beamforming apparatus for polarized antenna array is also provided in the invention as well as a radio communication device and a system thereof. With the invention, the single-layer and dual-layer beamforming weights are determined for the cross-polarized antenna array without requiring full channel knowledge or the aid of PMI. Computation complexity is lowered and full power amplifier utilization can be achieved.

First claim

The invention claimed is:

1. A beamforming method for a polarized antenna array comprising a plurality of antenna elements, applied to single layer beamforming or dual layer beamforming, the method comprising:
determining, by a base station, first beamforming weights for phase compensation among the antenna elements within each polarization direction;
determining, by the base station, second beamforming weights for phase compensation between equivalent channels of two polarization directions; and
calculating, by the base station, hybrid beamforming weights as a product of the first beamforming weights and the second beamforming weights.

2. The method according to claim 1 , wherein the step of determining first beamforming weights further comprises correlation vector calculation for each polarization direction.

3. The method according to claim 2 , wherein the correlation vector of two polarization directions is determined jointly.

4. The method according to claim 2 , wherein the correlation vector is filtered by a forgetting factor if continuous uplink channel coefficients are obtained in a time domain.

5. The method according to claim 1 , wherein the first beamforming weight for two different polarization directions is calculated as:

W
0

=

[

w
0
0

w
0
1

⋮

w
0

A
/
2

-
1

]

,

where
⁢

⁢

w
0
a

=

v
_

0
a



v
_

0
a



W
1

=

[

w
1
0

w
1
1

⋮

w
1

A
/
2

-
1

]

,

where
⁢

⁢

w
1
a

=

v
_

1
a



v
_

1
a



and wherein, w 0 a and w 1 a are with unit power, where a=0, 1, . . . , A/2−1 is an antenna index per polarization direction, A is the number of total antenna elements in the antenna array, and w 0 a , w 1 a are weighting factors for antenna element ‘a’ of 1 st and 2 nd polarized direction respectively.

6. The method according to claim 1 , wherein the phase compensation between the equivalent channels of two polarization directions is sub-band based.

7. A beamforming method according to claim 1 , wherein the step of determining second beamforming weights further comprises, calculating equivalent channels H 0 m ,H 1 m for each polarization direction by summing up channels of the antenna elements weighted by the beamforming weights within each polarization direction, as:

H
0
m

=

W
0
T

⁡

[

H

0
,
0

m

H

1
,
0

m

⋮

Assignees

• Hu Yang
• Astely David
• Guo Zhiheng
• Rahman Muhammad Imadur
• Wang Hai
• Zhang Ruiqi
• ERICSSON TELEFON AB L M (publ)

Inventors

• Hu Yang
• Astely David
• Guo Zhiheng
• Rahman Muhammad Imadur
• Wang Hai
• Zhang Ruiqi

Classifications

• H04B7/0671

  using different delays between antennas · CPC title

• H04B7/0691

  using subgroups of transmit antennas · CPC title

• H04B7/10

  Polarisation diversity; Directional diversity · CPC title

• H04B7/0617

  for beam forming · CPC title

• H04B7/0413

  MIMO systems · CPC title