# US 2016/0253288 A1 · Vector signal alignment for digital vector processing using vector transforms

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2016/0253288 A1
- Document ID: US20160253288A1
- Status: Published application
- Kind: A1
- Application number: 14/633,571
- Filed: 2015-02-27
- Published: 2016-09-01
- Earliest claimed: 2015-02-27
- Assignees: Alcatel-Lucent USA Inc.
- Applicants: Alcatel-Lucent USA Inc.
- Inventors: Ajit K. Reddy
- Web page: https://patentgrep.com/patent/US20160253288A1

## CPC

- G06F 17/14: Fourier, Walsh or analogous domain transformations {, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms (for correlation function computation G06F17/156; spectrum analysers G01R23/16)}
- H03F 1/3247: {using feedback acting on predistortion circuits (H03F1/3264 takes precedence)}
- H03F 3/24: of transmitter output stages
- H04B 1/04: Circuits
- H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)}
- H04L 25/49: using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels {; Baseband coding techniques specific to data transmission systems (spectral shaping H04L25/03828)}
- H03F 2201/3227: Adaptive predistortion based on amplitude, envelope or power level feedback from the output of the main amplifier
- H04B 2001/0425: {with linearisation using predistortion}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H03F: AMPLIFIERS
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A processor receives a first vector signal and a second vector signal from a circuit in response to the circuit receiving the first vector signal. The processor transforms the second vector signal from a time domain to a transform domain. The processor rotates the transformed second vector signal by a phase that is proportional to a time delay between the first and second vector signals to time-align the second vector signal to the first vector signal.

## Claims

### Claim 1

A method comprising:
receiving, at a processor, a second vector signal from a circuit in response to the circuit receiving a first vector signal;
transforming, at the processor, the second vector signal from a time domain to a transform domain; and
rotating, at the processor, the transformed second vector signal by a phase that is proportional to a time delay between the first and second vector signals to time-align the second vector signal to the first vector signal.

### Claim 2 (depends on 1)

The method of claim 1, wherein receiving the first vector signal comprises receiving a digital first vector signal, and wherein receiving the second vector signal comprises receiving a digital second vector signal from a circuit comprising at least one digital-to-analog converter to convert the digital first vector signal to an analog first vector signal, at least one low pass filter, a frequency up-converter, a bandpass filter, a power amplifier, a coupler to produce an analog second vector signal based on output from the power amplifier, a frequency down-converter, and at least one analog-to-digital converter to provide the digital second vector signal to the processor.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
pre-distorting the digital first vector signal based on the digital first vector signal and the time-aligned digital second vector signal to compensate for nonlinearity in the power amplifier.

### Claim 4 (depends on 1)

The method of claim 1, wherein transforming the second vector signal from the time domain to the transform domain comprises calculating an offset based on a sum of components of the second vector signal and subtracting the offset from the components of the second vector signal prior to transforming the offset-corrected second vector signal from the time domain to the transform domain.

### Claim 5 (depends on 4)

The method of claim 4, wherein transforming the offset-corrected second vector signal from the time domain to the transform domain comprises calculating a first vector power based on the first vector signal and a second vector power based on the offset-corrected second vector signal, calculating a gain based on a ratio of the first vector power to the second vector power, and scaling the offset-corrected second vector signal based on the gain prior to transforming the scaled second vector signal from the time domain to the transform domain.

### Claim 6 (depends on 1)

The method of claim 1, wherein transforming the second vector signal from the time domain to the transform domain comprises transforming the second vector signal on the basis of at least one of a first transform equation:
X

(
k
)
=
1
N

[
∑
m
=
0
N
2
-
1


x

(
2


m
)

U
N
/
2
mk
+
U
N
k

∑
m
=
0
N
2
-
1


x

(
2


m
+
1
)

U
N
/
2
mk
]
and a second transform equation:
X

(
k
)
=
1
N

[
∑
m
=
0
N
2
-
1


x

(
2


m
)

U
N
2


mk
+
∑
m
=
0
N
2
-
1


x

(
2


m
+
1
)

U
N
(
2


m
+
1
)

k
]
wherein X(k) represents the second vector signal in the transform domain, x( )represents the second vector signal in the time domain, N represents a number of samples in the second vector signal, and U represents a transform kernel.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
multiplying the rotated second vector signal and the transformed second vector signal to form a variance of the rotated second vector signal; and
transforming the variance of the rotated second vector signal from the transform domain to the time domain to form a time-aligned second vector signal.

### Claim 8 (depends on 7)

The method of claim 7, wherein transforming the variance of the rotated second vector signal from the transform domain to the time domain comprises transforming the variance of the rotated second vector signal on the basis of at least one of a first inverse transform equation:
x

(
m
)
=
1
N

[
∑
k
=
0
N
2
-
1


X

(
2


k
)

U
N
/
2
-
mk
+
U
N
-
k

∑
k
=
0
N
2
-
1


X

(
2


k
+
1
)

U
N
/
2
-
mk
]
and a second inverse transform equation:
x

(
m
)
=
1
N

[
∑
k
=
0
N
2
-
1


X

(
2


k
)

U
N
-
2


mk
+
∑
k
=
0
N
2
-
1


X

(
2


k
+
1
)

U
N
-
m

(
2


k
+
1
)
]
wherein X(k) represents the variance of the rotated second vector signal in the transform domain, x( )represents the variance of the rotated second vector signal in the time domain, N represents a number of samples in the second vector signal, and U represents a transform kernel.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
scaling the time-aligned second vector signal by a scaling factor determined based on a ratio of a product of the first vector signal and the time-aligned second vector signal to a magnitude of the time-aligned second vector signal.

### Claim 10

An apparatus, comprising:
a circuit to receive a first vector signal and generate a second vector signal in response to receiving the first vector signal; and
a processor to transform the second vector signal from a time domain to a transform domain and rotate the transformed second vector signal by a phase that is proportional to a time delay between the first and second vector signals to time-align the second vector signal to the first vector signal.

### Claim 11 (depends on 10)

The apparatus of claim 10, wherein the first vector signal is a digital first vector signal, and wherein the second vector signal is a digital second vector signal, and wherein the circuit comprises at least one digital-to-analog converter to convert the digital first vector signal to an analog first vector signal, at least one low pass filter, a frequency up-converter, a bandpass filter, a power amplifier, a coupler to produce an analog second vector signal based on output from the power amplifier, a frequency down-converter, and at least one analog-to-digital converter to provide the digital second vector signal to the processor.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the processor is to pre-distort the digital first vector signal based on the digital first vector signal and the time-aligned digital second vector signal to compensate for nonlinearity in the power amplifier.

### Claim 13 (depends on 10)

The apparatus of claim 10, wherein the processor is to calculate an offset based on a sum of components of the second vector signal and subtract the offset from the components of the second vector signal prior to transforming the offset-corrected second vector signal from the time domain to the transform domain.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein the processor is to calculate a first vector power based on the first vector signal and a second vector power based on the offset-corrected second vector signal, calculate a gain based on a ratio of the first vector power to the second vector power, and scale the offset-corrected second vector signal based on the gain prior to transforming the scaled second vector signal from the time domain to the transform domain.

### Claim 15 (depends on 10)

The apparatus of claim 10, wherein the processor is to transform the second vector signal on the basis of at least one of a first transform equation:
X

(
k
)
=
1
N

[
∑
m
=
0
N
2
-
1


x

(
2


m
)

U
N
/
2
mk
+
U
N
k

∑
m
=
0
N
2
-
1


x

(
2


m
+
1
)

U
N
/
2
mk
]
and a second transform equation:
X

(
k
)
=
1
N

[
∑
m
=
0
N
2
-
1


x

(
2


m
)

U
N
2


mk
+
∑
m
=
0
N
2
-
1


x

(
2


m
+
1
)

U
N
(
2


m
+
1
)

k
]
wherein X(k) represents the second vector signal in the transform domain, x( )represents the second vector signal in the time domain, N represents a number of samples in the second vector signal, and U represents a transform kernel.

### Claim 16 (depends on 10)

The apparatus of claim 10, wherein the processor is to multiply the rotated second vector signal and the transformed second vector signal to form a variance of the rotated second vector signal and transform the variance of the rotated second vector signal from the transform domain to the time domain to form a time-aligned second vector signal.

### Claim 17 (depends on 16)

The apparatus of claim 16, wherein the processor is to transform the variance of the rotated second vector signal on the basis of at least one of a first inverse transform equation:
x

(
m
)
=
1
N

[
∑
k
=
0
N
2
-
1


X

(
2


k
)

U
N
/
2
-
mk
+
U
N
-
k

∑
k
=
0
N
2
-
1


X

(
2


k
+
1
)

U
N
/
2
-
mk
]
and a second inverse transform equation:
x

(
m
)
=
1
N

[
∑
k
=
0
N
2
-
1


X

(
2


k
)

U
N
-
2


mk
+
∑
k
=
0
N
2
-
1


X

(
2


k
+
1
)

U
N
-
m

(
2


k
+
1
)
]
wherein X(k) represents the variance of the rotated second vector signal in the transform domain, x( )represents the variance of the rotated second vector signal in the time domain, N represents a number of samples in the second vector signal, and U represents a transform kernel.

### Claim 18 (depends on 16)

The apparatus of claim 16, wherein the processor is to scale the time-aligned second vector signal by a scaling factor determined based on a ratio of a product of the first vector signal and the time-aligned second vector signal to a magnitude of the time-aligned second vector signal.

### Claim 19

A non-transitory computer readable medium embodying a set of executable instructions, the set of executable instructions to manipulate a processor to:
receive a first vector signal and a second vector signal from a circuit in response to the circuit receiving the first vector signal;
transform the second vector signal from a time domain to a transform domain; and
rotate the transformed second vector signal by a phase that is proportional to a time delay between the first and second vector signals to time-align the second vector signal to the first vector signal.

### Claim 20 (depends on 19)

The non-transitory computer readable medium of claim 19, wherein the first vector signal is a digital first vector signal, and wherein the second vector signal is a digital second vector signal, and wherein the set of executable instructions manipulate the processor to pre-distort the digital first vector signal based on the digital first vector signal and the time-aligned digital second vector signals to compensate for nonlinearity in a power amplifier implemented in the circuit.

### Claim 21 (depends on 19)

The non-transitory computer readable medium of claim 19, wherein the set of executable instructions manipulate the processor to calculate an offset based on a sum of components of the second vector signal and subtract the offset from the components of the second vector signal prior to transforming the offset-corrected second vector signal from the time domain to the transform domain.

### Claim 22 (depends on 21)

The non-transitory computer readable medium of claim 21, wherein the set of executable instructions manipulate the processor to calculate a first vector power based on the first vector signal and a second vector power based on the offset-corrected second vector signal, calculate a gain based on a ratio of the first vector power to the second vector power, and scale the offset-corrected second vector signal based on the gain prior to transforming the scaled second vector signal from the time domain to the transform domain.

### Claim 23 (depends on 19)

The non-transitory computer readable medium of claim 19, wherein the set of executable instructions manipulate the processor to multiply the rotated second vector signal and the transformed second vector signal to form a variance of the rotated second vector signal and transform the variance of the rotated second vector signal from the transform domain to the time domain to form a time-aligned second vector signal.

### Claim 24 (depends on 23)

The non-transitory computer readable medium of claim 23, wherein the set of executable instructions manipulate the processor to scale the time-aligned second vector signal by a scaling factor determined based on a ratio of a product of the first vector signal and the time-aligned second vector signal to a magnitude of the time-aligned second vector signal.