IQ-modulator pre-distortion
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorLeonard Rexberg
Life of this patent
Estimating the term…
Abstract
An IQ-modulator pre-distorter includes means for pre-distorting each IQ-vector by a 2-dimensional linear transformation that depends on the value of the IQ-vector to be pre-distorted. The transformation is based on polynomials in the I- and Q-components. In a preferred embodiment the transformation is based on a 2×2 dimensional lookup table matrix, the elements (T11, T12, T21, T22) of which are sampled polynomials in the I- and Q-components of the IQ-vector.
Claims3
An IQ-modulator pre-distortion method, said method comprising the step of pre-distorting each IQ-vector by a 2-dimensional linear transformation that depends on the value of the IQ-vector to be pre-distorted, wherein said transformation is based on polynomials in the I- and Q-components of said IQ-vector, wherein said transformation is based on a 2×2 dimensional lookup table matrix, the elements of which are sampled polynomials in the I- and Q-components of said IQ-vector, wherein one of the diagonal elements and one of the off-diagonal elements of said matrix depend on said I-component and the other diagonal element and the other off-diagonal element depend on said Q-component, and wherein said transformation is represented by the equation:
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- =
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
-
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- +
- [
- α
- 0
- β
- 0
- ]
- where
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- is the IQ-vector to be pre-distorted,
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
- is said matrix,
- [
- α
- 0
- β
- 0
- ]
- is an offset vector,
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- is the pre-distorted vector, and
- t is a variable representing time.
An IQ-modulator pre-distorter, comprising:
- means for pre-distorting each IQ-vector by a 2-dimensional linear transformation that depends on the value of the IQ-vector to be pre-distorted, wherein said transformation is based on polynomials in the I- and Q-components of said IQ-vector, wherein said transformation is based on a 2×2 dimensional lookup table matrix, the elements of which are sampled polynomials in the I- and Q-components of said IQ-vector, wherein one of the diagonal elements and one of the off-diagonal elements of said matrix depend on said I-component and the other diagonal element and the other off-diagonal element depend on said Q-component, and wherein said transformation is represented by the equation:
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- =
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
-
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- +
- [
- α
- 0
- β
- 0
- ]
- where
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- is the IQ-vector to be pre-distorted,
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
- said matrix,
- [
- α
- 0
- β
- 0
- ]
- is an offset vector,
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- is the pre-distorted vector, and
- t is a variable representing time, and
- means for outputting each pre-distorted IQ vector.
A base station including an IQ-modulator pre-distorter, said pre-distorter comprising:
- means for pre-distorting each IQ-vector by a 2-dimensional linear transformation that depends on the value of the IQ-vector to be pre-distorted, wherein said transformation is based on polynomials in the I- and Q-components of said IQ-vector, wherein said transformation is based on a 2×2 dimensional lookup table matrix, the elements of which are sampled polynomials in the I- and Q-components of said IQ-vector, wherein one of the diagonal elements and one of the off-diagonal elements of said matrix depend on said I-component and the other diagonal element and the other off-diagonal element depend on said Q-component, and wherein said transformation is represented by the equation:
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- =
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
-
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- +
- [
- α
- 0
- β
- 0
- ]
- where
- [
- I
-
- (
- t
- )
- Q
-
- (
- t
- )
- ]
- is the IQ-vector to be pre-distorted,
- [
- T
- 11
-
- (
- I
-
- (
- t
- )
- )
- T
- 12
-
- (
- Q
-
- (
- t
- )
- )
- T
- 21
-
- (
- I
-
- (
- t
- )
- )
- T
- 22
-
- (
- Q
-
- (
- t
- )
- )
- ]
- said matrix,
- [
- α
- 0
- β
- 0
- ]
- is an offset vector,
- [
- I
- ′
-
- (
- t
- )
- Q
- ′
-
- (
- t
- )
- ]
- is the pre-distorted vector, and
- t is a variable representing time, and
- means for outputting each pre-distorted IQ vector.
Dependencies are inferred from the claim text.