System and method for performing fast transmission output power transition

Patent metadata

Field	Value
Publication number	US-12431852-B2
Application number	US-202217943399-A
Country	US
Kind code	B2
Filing date	Sep 13, 2022
Priority date	Sep 13, 2022
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

This disclosure is directed to compensating for gain drift due to switching the output power of a transmitter of an electronic device. In some cellular network applications, the transmit power level of a transmitter may be frequently adjusted from a low power level to a high power level. If the power level is not switched to the desired power level within a given interval, the transmission signal may be distorted. To enable the transmitter to reach a desired output power within the interval, the voltage supply of a power amplifier may be raised during a low power symbol, which may produce an undesirable gain increase. To mitigate or eliminate the low power symbol gain increase, a gain compensation signal may be introduced into the transmitter. The compensation signal may be adjusted and refined by implementing a power control loop, the power control loop may include a power controller.

First claim

What is claimed is:

1. A transmitter, comprising:
a mixer configured to output a compensated signal based on an input signal and a compensation signal that compensates for excess gain at a symbol of the input signal;
a power amplifier electrically coupled to the mixer, the power amplifier configured to amplify the compensated signal to generate an amplified signal; and
a power controller electrically coupled to the power amplifier on a feedback path of the transmitter, the power controller configured to adjust the compensation signal based on a deviation in gain of the compensated signal.

2. The transmitter of claim 1 , comprising a reference selector electrically coupled to the mixer and the power controller, the reference selector configured to obtain amplitude modulation data regarding the input signal and output the amplitude modulation data to the power controller.

3. The transmitter of claim 1 , wherein the power controller is configured to sample the compensated signal N number of times within the symbol, and determine the deviation based on the N number of samples.

4. The transmitter of claim 1 , wherein the power controller is configured to adjust the compensation signal by adjusting a voltage level of the compensated signal.

5. The transmitter of claim 1 , wherein the compensation signal is determined, via a processor, based on a compensation profile, the compensation profile based on a shape, an amplitude, or both of a gain ramp associated with the symbol of the input signal determined during a calibration.

6. The transmitter of claim 1 , wherein the power amplifier is configured to operate in an average power tracking mode.

7. The transmitter of claim 1 , comprising memory digital pre-distortion circuitry electrically coupled to the mixer, the memory digital pre-distortion circuitry configured to perform linearization on the compensated signal.

8. The transmitter of claim 7 , comprising a digital front end electrically coupled to the mixer, the digital front end configured to perform frequency conversion, channel filtering, or both on the compensated signal.

9. The transmitter of claim 8 , comprising a digital-to-analog converter (DAC) electrically coupled to the digital front end and the power amplifier, the DAC configured to convert the input signal from a digital signal to an analog signal and pass the analog signal to the power amplifier.

10. The transmitter of claim 1 , wherein the symbol comprises a low power orthogonal frequency division multiplexing (OFDM) symbol.

11. A method, comprising:
increasing a supply voltage of a power amplifier during transmission of a low power symbol of a transmit signal that is to transition to a high power symbol;
applying a gain compensation to the transmit signal to reduce a gain associated with the low power symbol to generate a compensated signal;
adjusting the gain compensation based on a deviation of the gain to generate an adjusted gain compensation; and
applying the adjusted gain compensation to the compensated signal.

12. The method of claim 11 , wherein applying the adjusted gain compensation comprises applying the adjusted gain compensation during a subsequent clock cycle of the low power symbol.

13. The method of claim 11 , wherein adjusting the gain compensation comprises adjusting a voltage of a gain compensation signal.

14. The method of claim 11 , comprising
determining another deviation during a subsequent clock cycle of the low power symbol; and
refraining from adjusting the gain compensation in response to determining that the other deviation falls beneath a gain deviation threshold.

15. The method of claim 11 , comprising applying the gain compensation to the transmit signal to reduce the gain associated with the low power symbol to a target gain of 0 decibels.

16. The method of claim 11 , wherein determining the gain of the compensated signal comprises sampling the gain N number of times during the transmission of the low power symbol.

17. A tangible, non-transitory, computer-readable medium comprising machine-readable instructions, wherein the instructions are configured to cause one or more processors of an electronic device to:
increase a supply voltage of a power amplifier during transmission of a low power symbol of a transmit signal that is to transition to a high power symbol;
apply a gain compensation to reduce a gain associated with the low power symbol to generate a compensated signal;
adjust the gain compensation based on a deviation of the gain to generate an adjusted gain compensation; and
apply the adjusted gain compensation to the compensated signal.

18. The tangible, non-transitory, computer-readable medium of claim 17 , comprising machine-readable instruction, wherein the instructions are configured to cause the one or more processors of the electronic device to determine the deviation by sampling the gain N number of times during the transmission of the low power symbol.

19. The tangible, non-transitory, computer-readable medium of claim 18 , wherein causing the one or more processors to sample the gain N number of times during the transmission of the low power symbol comprises causing the one or more processors to sample the gain every clock cycle of the low power symbol.

20. The tangible, non-transitory, computer-readable medium of claim 17 , wherein causing the one or more processors to adjust the gain compensation comprises causing the one or more processors to adjust the gain compensation based on amplitude modulation data associated with the transmit signal.

Assignees

• Apple Inc

Inventors

• Camuffo Andrea
• Langer Andreas
• Hackl Guenther
• Henzler Stephan

Classifications

• H04W52/52 Primary

  using AGC [Automatic Gain Control] circuits or amplifiers · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title

• H03F3/245

  with semiconductor devices only · CPC title

• H03F3/195

  in integrated circuits · CPC title

• H03G3/3042 Primary

  in modulators, frequency-changers, transmitters or power amplifiers · CPC title