Predistorter, predistorter controller, and high power amplifier linearization method

Patent metadata

Field	Value
Publication number	US-11316583-B2
Application number	US-201916707927-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Dec 9, 2019
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

The present disclosure provides a high power amplifier (HPA) linearization method, applied to a ground hub which includes a predistorter and a PD controller. The ground hub is arranged in a satellite communication system together with a transmitter and a satellite transponder, and the satellite transponder includes an HPA. The HPA linearization method includes determining an initial correction signal based on a physical model with a plurality of PD parameters to compensate AM-AM and AM-PM characteristics of the HPA; receiving a signal from the satellite transponder; determining a reward function for an action taken by the PD controller; examining an action-value function for actions taken in a preset past period; taking an action to adjust the plurality of PD parameters for the PD to generate an updated correction signal; sending the update correction signal to the transmitter to compensate the AM-AM and AM-PM characteristics of the HPA.

First claim

What is claimed is:

1. A high power amplifier (HPA) linearization method, applied to a ground hub which includes a predistorter (PD) and a PD controller, wherein the PD controller stores a database including a set of environmental parameters and a set of PD parameters corresponding to the set of environmental parameters, the ground hub is arranged in a satellite communication (SATCOM) system together with a transmitter and a satellite transponder, and the satellite transponder includes an HPA, the method comprising:
determining an initial correction signal including an amplitude modulation-to-amplitude modulation (AM-AM) correction signal and an amplitude modulation-to-phase modulation (AM-PM) correction signal based on a physical model with a plurality of PD parameters, and sending the initial correction signal to the transmitter to compensate AM-AM and AM-PM characteristics of the HPA;
receiving a signal from the satellite transponder;
determining a reward function for an action taken by the PD controller based on the received signal and environmental parameters;
examining an action-value function for actions taken in a preset past period based on reward functions of the actions;
taking an action, based on the environment parameters and the action-value function, to adjust the plurality of PD parameters for the PD to generate an updated correction signal;
sending the update correction signal to the transmitter to compensate the AM-AM and AM-PM characteristics of the HPA; and
updating the database in a real-time manner according to the environment parameters, the plurality of PD parameters, and the action-value function.

2. The method according to claim 1 , wherein determining, by the PD, the initial correction signal based on the physical model with more than four PD parameters includes:
sending a signal to the satellite transponder from the ground hub through the transmitter and receiving a signal sent back from the satellite transponder to the ground hub;
calculating the AM-AM and AM-PM characteristics of the HPA according to the signal sent to the satellite transponder and the signal received from the satellite transponder;
simulating the AM-AM and AM-PM characteristics of the HPA using the physical model with the plurality of PD parameters; and
determining the initial correction signal, including the AM-AM correction signal and the AM-PM correction signal, based on obtained values of the plurality of PD parameters.

3. The method according to claim 2 , wherein simulating the AM-AM and AM-PM characteristics of the HPA further includes:
fitting the AM-AM characteristics of the HPA by

α
0

⁢

ρ

y
⁡

(
t
)

a
0

+

β
0

⁡

(

ρ

y
⁡

(
t
)

+

b
0

)

2

,

where ρ y(t) is an amplitude of an input complex signal, and a 0 , b 0 , α 0 , and β 0 are four PD parameters of the plurality of PD parameters; and
fitting the AM-PM characteristics of the HPA by

α
1

⁢

ρ

y
⁡

(
t
)

2

a
1

+

β
1

⁡

(

ρ

y
⁡

(
t
)

+

b
1

)

2

,

where a 1 , b 1 , α 1 , and β 1 are four PD parameters of the plurality of PD parameters.

4. The method according to claim 3 , wherein:
a least-squares criterion is used to determine fits to the AM-AM and AM-PM characteristics of the HPA.

5. The method according to claim 3 , wherein determining the initial correction signal based on the obtained values of the plurality of PD parameters includes:
determining the AM-AM correction signal as

{

(

α
0

-

2
⁢

b
0

⁢

β
0

⁢

ρ

x
⁡

(
t

Assignees

• Intelligent Fusion Tech Inc

Inventors

• Li Lun
• Lu Jingyang
• Nguyen John
• Shen Dan
• Pham Khanh
• Chen Genshe

Classifications

• G06N7/01

  Probabilistic graphical models, e.g. probabilistic networks · CPC title

• G06N3/092

  Reinforcement learning · CPC title

• H03F3/189

  High-frequency amplifiers, e.g. radio frequency amplifiers · CPC title

• H03F3/24

  of transmitter output stages · CPC title

• H04B7/18519 Primary

  Operations control, administration or maintenance · CPC title