US 8,265,697 B2Granted

Restricted multi-rank precoding in multiple antenna systems

AssigneeNEC Laboratories America, Inc.

InventorMohammad A. Khojastepour

Life of this patent

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Abstract

A quantized multi-rank beamforming scheme for multiple-antenna systems such as a multiple-input-multiple-output (MIMO) wireless downlink User equipment (UE) estimates downlink channel and transmit power and determines rank and power allocations. A quantized beamforming matrix is then determined by the UE using successive beamforming. The UE also determines channel quality indices (CQI) which it feeds-back to the wireless downlink base station along with the index of the quantized beamforming matrix. The base station uses the CQI information to select a UE for scheduling of downlink transmission and the quantized beamforming matrix index received from the selected UE to beamform the downlink transmission to the UE. Base station overhead and is minimized while providing near-optimal performance given the constraints of a limited feed-back channel and computational complexity of the UE.

Claims9

Dependent claims

A method implemented in a base station of performing multi-rank, quantized beamforming, comprising:

precoding data using a precoding matrix that is selected from a codebook comprising codebook entries V in the form
V
=
[
v
1
,
Φ
⁡
(
v
1
1
)
⁢
HH
(
v
1
Φ
⁡
(
v
1
1
)
-
e
1
M
)
⁡
[
0
v
2
]
,
Φ
⁡
(
v
1
1
)
⁢
HH
(
v
1
Φ
⁡
(
v
1
1
)
-
e
1
M
)
⁡
[
0
Φ
⁡
(
v
1
2
)
⁢
HH
(
v
2
Φ
⁡
(
v
1
2
)
-
e
1
M
-
1
)
⁡
[
0
v
3
]
]
]
,
…
where the base station has M=4 antennas, e1N=[1,0, . . . , 0]TεCN (N=M, M−1, . . . ), CN being N-dimensional complex space, va denotes a column vector, vba denotes the bth element of the vector va,
Φ
⁡
(
v
b
a
)
=
v
b
a

v
b
a

,
and
⁢
⁢
HH
⁡
(
w
)
=
{
I
-
2
⁢
⁢
ww
H

w

2
if
w
≠
0
I
if
w
=
0
⁢
⁢
is
is the house-holder transformation of the vector w and va is selected from a set Va where V1=½{[1, 1, 1, 1]T, [1, −j, −1, j]T, [1, −1, 1, −1]T, [1, j, −1, −j]T, [1, f, −j, −g]T, [1, −g, j, f]T, [1, −f, −j, g]T, [1, g, j, −f]T, [1, 1, −1, −1]T, [1, −j, 1, −j]T, [1, −1, −1, 1]T, [1, j, 1, j]T, [1, 1, 1, −1]T, [1, 1, −1, 1]T, [1, −1, 1, 1]T, [1, −1, −1, −1]T}, where f=(1−j)/√{square root over (2)}, g=(1+j)/√{square root over (2)}, and j=√{square root over (−1)}, V2={e13}, V3={e12}, and V4={e11};
and
transmitting the precoded data to a mobile terminal.

152 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/155,700Filed 8 Jun 2011 · division
Priority: 14 Feb 2006
Published: US 2011/0194400 A13 Nov 2011
Granted: 11 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

H04B 7/0617
Of weighted versions of same signal: for beam forming
H04B 7/0408
Using two or more spaced independent antennas: using two or more beams, i.e. beam diversity
H04B 7/0413
Using two or more spaced independent antennas: mIMO systems
H04B 7/0456
MIMO systems: selection of precoding matrices or codebooks, e.g. using matrices antenna weighting

Family

Application60/743,290Us provisional application · filed 14 Feb 2006
Application11/674,330Parent of this division · filed 13 Feb 2007
Application13/029,465Parent of this division · filed 17 Feb 2011
US 7,917,176 B2Parent of this division · filed 29 Mar 2011
US 2011/0268210 A1Pre-grant publication · published 3 Nov 2011
US 8,103,312 B2Parent of this division
US 2007/0191066 A1Published application
US 2011/0194400 A1Published application
US 8,265,697 B2This patent

From the US filing history. Foreign family members aren’t listed.