US 7,068,102 B2Granted

Power amplifying apparatus and method using pre-distortion and radio communication system including the same apparatus

AssigneeDANAM Inc.

InventorsVincent Inkyou Hwang, Yongsub Kim, Chen Liu

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Abstract

A new concept of power amplifying apparatus and method is developed for adopting pre-distortion and applying to a radio communication system. The power amplifying apparatus includes a pre-distortion module for pre-distorting an input signal x(n) according to a pre-distortion function, and for outputting a pre-distorted signal z(n), a power amplifier for amplifying a signal obtained by digital-to-analog conversion of the pre-distorted signal z(n), a pre-distortion function producing module for receiving the pre-distorted signal z(n) and a signal y(n) obtained by analog-to-digital conversion of the fed-back output signal of the power amplifier, and for obtaining model coefficients cq,k,s that minimize the power of a modeling error signal e(n)=z(n)−y(n). The pre-distortion function used by the pre-distortion module is represented as z ⁡ ( n ) = ∑ q = 0 Q ⁢ ∑ k = 1 K ⁢ ∑ s = - S min ⁢ ⁢ ( S , q ) ⁢ c q , k , s ⁢ y ⁡ ( n - q + s ) ⁢  y ⁡ ( n - q )  k - 1 .

Claims6

Dependent claims

A power amplifying apparatus using pre-distortion, comprising:

a pre-distortion module for pre-distorting an input signal x(n) according to a pre-distortion function, and for outputting a predistorted signal z(n),
a power amplifier for amplifying a signal obtained by digital-to-analog conversion of the pre-distorted signal z(n), and
a pre-distortion function producing module for receiving the pre-distorted signal z(n) and a signal y(n) obtained by analog-to-digital conversion of the fed-back output signal of the power amplifier, and for obtaining model coefficents cq,k,s that minimize the power of a modeling error signal e(n)=z(n)−y(n), said pre-distortion function used by the pre-distortion module represented as,
z
⁡
(
n
)
=
∑
q
=
0
Q
⁢
∑
k
=
1
K
⁢
∑
s
=
-
S
min
⁡
(
S
,
q
)
⁢
c
q
,
k
,
s
⁢
y
⁡
(
n
-
q
+
s
)
⁢

y
⁡
(
n
-
q
)

k
-
1
wherein, Q is a maximum number of memory depth in an actual implementation, K is a maximum order of nonlinear polynomial to be implemented in the pre-distortion system, S is a maximum memory depth of cross-memory terms to be considered in the pre-distortion implementation, q is an indexing variable for summation operation over memory from 0 up to Q, k is an indexing variable for summation operation over polynomial order from 1 up to K, s is an indexing variable for summation operation over cross-memory depth from −S up to min(S, q) and cq,k,s is a model coefficient corresponding to the specific values of q, k and s.

61 more elements

A radio communication system including a power amplifying apparatus using pre-distortion, the power amplifying apparatus comprises:

a pre-distortion module for pre-distorting an input signal x(n) according to a pre-distortion function, and for outputting a pre-distorted signal z(n),
a power amplifier for amplifying a signal obtained by digital-to-analog conversion of the pre-distorted signal z(n), and
a pre-distortion function producing module for receiving the pre-distorted signal z(n) and a signal y(n) obtained by analog-to-digital conversion of the fed-back output signal of the power amplifier, and for obtaining model coefficients cq,k,s that minimize the power of a modeling error signal e(n)=z(n)−y(n), said pre-distortion function used by the pre-distortion module represented as,
z
⁡
(
n
)
=
∑
q
=
0
Q
⁢
∑
k
=
1
K
⁢
∑
s
=
-
S
min
⁡
(
S
,
q
)
⁢
c
q
,
k
,
s
⁢
y
⁡
(
n
-
q
+
s
)
⁢

y
⁡
(
n
-
q
)

k
-
1
wherein, Q is a maximum number of memory depth in an actual implementation, K is a maximum order of nonlinear polynomial to be implemented in the pre-distortion system, S is a maximum memory depth of cross-memory terms to be considered in the pre-distortion implementation. q is an indexing variable for summation operation over memory from 0 up to Q, k is an indexing variable for summation operation over polynomial order from 1 up to K, s is an indexing variable for summation operation over cross-memory depth from −S up to min(S, q) and cq,k,s is a model coefficient corresponding to the specific values of q, k and s.

61 more elements

A power amplifying method using pre-distortion, comprising:

a pre-distortion step of pre-distorting an input signal x(n) according to a pre-distortion function, and of outputting a pre-distorted signal z(n),
a power amplification step of amplifying a signal obtained by digital-to-analog conversion of the pre-distorted signal z(n), and
a pre-distortion function producing step of receiving the pre-distorted signal z(n) and a signal y(n) obtained by analog-to-digital conversion of the fed-back output signal of the power amplifier, and of obtaining model coefficients cq,k,s that minimize the power of a modeling error signal e(n)=z(n)−y(n), said pre-distortion function used in the pre-distortion step represented as,
z
⁡
(
n
)
=
∑
q
=
0
Q
⁢
∑
k
=
1
K
⁢
∑
s
=
-
S
min
⁡
(
S
,
q
)
⁢
c
q
,
k
,
s
⁢
y
⁡
(
n
-
q
+
s
)
⁢

y
⁡
(
n
-
q
)

k
-
1
wherein, Q is a maximum number of memory depth in an actual implementation, K is a maximum order of nonlinear polynomial to be implemented in the pre-distortion system, S is a maximum memory depth of cross-memory terms to be considered in the pre-distortion implementation, q is an indexing variable for summation operation over memory from 0 up to Q, k is an indexing variable for summation operation over polynomial order from 1 up to K, s is an indexing variable for summation operation over cross-memory depth from −S up to min(S, q) and cq,k,s is a model coefficient corresponding to the specific values of q, k and s.

61 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/884,835Filed 2 Jul 2004
Priority: KR 10-2003-004665310 Jul 2003
Published: US 2005/0007193 A113 Jan 2005
Granted: 27 Jun 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H03F 1/3258
Using predistortion circuits: based on polynomial terms
H03F 1/26
Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements: modifications of…
H03F 1/3247
Using predistortion circuits: using feedback acting on predistortion circuits
H03F 2201/3233
Indexing scheme relating to modifications of amplifiers to reduce non-linear distortion: adaptive predistortion using lookup table, e.g. memory,…