Wireless communication apparatus, Doherty amplifier, and method for controlling wireless communication

Patent metadata

Field	Value
Publication number	US-9231626-B2
Application number	US-201314049013-A
Country	US
Kind code	B2
Filing date	Oct 8, 2013
Priority date	Dec 3, 2012
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A wireless communication apparatus includes: a first amplifier configured to amplify an input signal; a second amplifier configured to amplify the input signal when an input level of the input signal is equal to or larger than a given level; an impedance converter configure to switch an load impedance of the first amplifier and output a composite output of an output from the first amplifier and an output from the second amplifier; an impedance controller section configured to control a switching of the load impedance of the first amplifier based on a bandwidth of the input signal; a distortion compensation section configured to perform distortion compensation of the input signal and supply a compensated input signal to the first amplifier and the second amplifier; and a filter section configured to limit a band of a signal output from the impedance converter.

First claim

What is claimed is:

1. A wireless communication apparatus comprising:
a first amplifier configured to amplify an input signal;
a second amplifier configured to amplify the input signal when an input level of the input signal is equal to or larger than a given level;
an impedance converter configured to switch a load impedance of the first amplifier and output a composite output comprising an output from the first amplifier and an output from the second amplifier, the impedance converter comprising a first capacitor coupled to a transmission channel via a first switch;
an impedance controller section configured to control a switching of the load impedance of the first amplifier such that a first switching is performed as the switching when a bandwidth of the input signal is equal to or less than a given value and a second switching is performed as the switching when the bandwidth of the input signal is greater than the given value;
a distortion compensation section configured to perform distortion compensation of the input signal and output a compensated input signal to the first amplifier and the second amplifier; and
a filter section configured to limit a band of a signal output from the impedance converter.

2. The wireless communication apparatus according to claim 1 ,
a transmission channel configured to transmit the composite output.

3. The wireless communication apparatus according to claim 2 , wherein the load impedance of the first amplifier is switched based on a state of the first switch.

4. The wireless communication apparatus according to claim 1 , wherein the impedance converter further comprises
a second capacitor coupled to the transmission channel via a second switch.

5. The wireless communication apparatus according to claim 1 , wherein the impedance controller section is further configured to control the switching to become the first switching such that the load impedance or the first amplifier becomes substantially equal to an impedance at an output of the impedance converter when the bandwidth of the input signal is equal to or less than the given value.

6. The wireless communication apparatus according to claim 1 , wherein the impedance controller section is further configured to control the switching to become the first switching such that the load impedance of the first amplifier becomes substantially equal to an impedance at an output of the impedance converter when the bandwidth of the input signal is equal to or less than the given value and transmission power of the input signal is equal to or less than a given power.

7. The wireless communication apparatus according to claim 1 , wherein the impedance controller section is further configured to control the switching to become the second switching such that the load impedance of the first amplifier becomes larger than an impedance at an output of the impedance converter when the bandwidth of the input signal is greater than the given value.

8. The wireless communication apparatus according to claim 7 , wherein the impedance controller section is further configured to control the switching to become the second switching such that the load impedance of the first amplifier becomes twice the impedance at the output of the impedance converter.

9. The wireless communication apparatus according to claim 1 , wherein the impedance controller section is further configured to control the switching of the load impedance of the first amplifier based on a transmission power level of the input signal.

10. The wireless communication apparatus according to claim 1 , wherein the given value is approximately one-third of a maximum bandwidth of the input signal.

11. A Doherty amplifier comprising:
a first amplifier configured to amplify an input signal;
a second amplifier configured to amplify the input signal when a level of the input signal is equal to or larger than a given level;
an impedance converter configured to switch a load impedance of the first amplifier and output a composite output comprising an output from the first amplifier and an output from the second amplifier, the impedance converter comprising a first capacitor coupled to a transmission channel via a first switch; and
an impedance controller section configured to control a switching of the load impedance of the first amplifier based on a bandwidth of the input signal such that a first switching is performed as the switching of the load impedance of the first amplifier when the bandwidth of the input signal is equal to or less than a given value and a second switching is performed as the switching when the bandwidth of the input signal is greater than the given value.

12. A method for controlling wireless communication comprising:
performing distortion compensation of an input signal and supplying the compensated input signal to a first amplifier and a second amplifier;
amplifying the input signal via the first amplifier;
amplifying the input signal via the second amplifier when an input level of the input signal is equal to or larger than a given level;
switching an load impedance of the first amplifier such that a first switching is performed as the switching when a bandwidth of the input signal is equal to or less than a given value and a second switching is performed as the switching when the bandwidth of the input signal is greater than the given value;
outputting to an impedance converter a composite output comprising an output from the first amplifier and an output from the second amplifier based on a bandwidth of the input signal, the impedance converter comprising a first capacitor coupled to a transmission channel via a first switch; and
limiting a band of a signal output from an impedance converter.

13. A wireless communication apparatus comprising:
a first amplifier configured to amplify an input signal;
a second amplifier configured to amplify the input signal when an input level of the input signal is equal to or larger than a given level;
an impedance converter configured to switch a load impedance of the first amplifier and receive a composite output comprising an output from the first amplifier and an output from the second amplifier;
an impedance controller section configured to control a switching of the load impedance of the first amplifier based on a bandwidth of the input signal; and
a distortion compensation section configured to perform distortion compensation of the input signal and supply a compensated input signal to the first amplifier and the second amplifier,
wherein the impedance converter includes:
a transmission channel configured to transmit the composite output; and
a first capacitor coupled to the transmission channel via a first switch.

14. The wireless communication apparatus according to claim 13 , wherein the load impedance of the first amplifier is switched based on a state of the first switch.

15. The wireless communication apparatus according to claim 13 , wherein the impedance converter comprises a second capacitor coupled to the transmission channel via a second switch.

16. The wireless communication apparatus according to claim 13 , wherein the impedance controller section is further configured to control the switching so that the load impedance of the first amplifier becomes substantially equal to an impedance at an output of the impedance converter when the bandwidth of the input signal is equal to or less than a given value.

17. The wireless communication apparatus according to claim 13 , wherein the impedance controller section is configured to control the switching such that

Assignees

• Fujitsu Ltd

Inventors

• Okazaki Yousuke
• Maeda Hiroaki
• Honda Hirotake
• Shizawa Yoshinobu
• Ogawa Hiroyuki
• Okawa Yasuhiro

Classifications

• H04B2001/0425

  with linearisation using predistortion · CPC title

• H03F1/0288

  using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers · CPC title

• H03F2200/111

  the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not · CPC title

• H03F2200/387

  A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier · CPC title

• H03F1/56

  Modifications of input or output impedances, not otherwise provided for · CPC title