US-12628097-B2 - System and method for performing fast transmission output power transition

US12628097B2US 12628097 B2US12628097 B2US 12628097B2US-12628097-B2

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 signal generator.

Inventors

Andrea Camuffo
Andreas Langer
Guenther Hackl
Stephan Henzler

Assignees

APPLE INC.

Dates

Publication Date: 20260512
Application Date: 20220913

Claims (20)

1 . A transmitter, comprising: a first mixer configured to output a compensated signal based on an input signal and a first compensation signal; a power amplifier electrically coupled to the first mixer, the power amplifier configured to amplify the compensated signal to generate an amplified signal; a signal generator electrically coupled to the power amplifier on a feedback path of the transmitter, the signal generator configured to output a second compensation signal based on a deviation in gain of the compensated signal; and a second mixer configured to apply the second compensation signal to the compensated signal.
2 . The transmitter of claim 1 , wherein the input signal comprises a signal that is to transition from a low power symbol to a high power symbol.
3 . The transmitter of claim 2 , wherein the signal generator is configured to output the second compensation signal to a subsequent low power symbol of the input signal, the second compensation signal configured to mitigate the deviation associated with the compensated signal.
4 . The transmitter of claim 1 , comprising a reference selector electrically coupled to the first mixer and the signal generator, the reference selector configured to obtain modulation data regarding the input signal and output the modulation data to the signal generator.
5 . The transmitter of claim 4 , wherein the modulation data comprises amplitude modulation data.
6 . The transmitter of claim 1 , wherein the first compensation signal is determined via a processor, the first compensation signal based on a compensation profile, the compensation profile based on a shape, an amplitude, or both of a gain ramp associated with a symbol of the input signal.
7 . The transmitter of claim 1 , comprising memory digital pre-distortion circuitry electrically coupled to the first 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 first 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 compensated 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 input signal comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols.
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 first gain compensation signal to the low power symbol of the transmit signal to reduce a gain associated with the low power symbol to generate a compensated transmit signal; generating a second gain compensation signal based on a deviation of the gain; and applying the second gain compensation signal to a subsequent symbol of the transmit signal.
12 . The method of claim 11 , wherein the gain associated with the low power symbol comprises an instantaneous output amplitude.
13 . The method of claim 12 , wherein the second gain compensation signal comprises a linear compensation ramp, an exponential compensation ramp, or a combination thereof.
14 . The method of claim 11 , comprising: determining that another deviation of another subsequent symbol falls beneath a gain deviation threshold; and refraining from generating another gain compensation.
15 . The method of claim 11 , wherein applying the first gain compensation signal to the low power symbol to reduce the gain comprises reducing the gain to a target gain of 0 decibels.
16 . The method of claim 11 , wherein the power amplifier is configured to operate in an average power tracking mode.
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 first gain compensation signal reduce a gain associated with the low power symbol to generate a compensated signal; generate a second gain compensation signal based on a deviation of the gain; and apply the second gain compensation signal to the transmit signal during transmission of a subsequent low power symbol.
18 . The tangible, non-transitory, computer-readable medium of claim 17 , wherein the gain associated with the low power symbol comprises an instantaneous output amplitude.
19 . The tangible, non-transitory, computer-readable medium of claim 17 , wherein causing the one or more processors to generate the second gain compensation signal comprises generating the second gain compensation signal based on an amplitude modulation of the low power symbol.
20 . The tangible, non-transitory, computer-readable medium of claim 17 , wherein the low power symbol and the high power symbol each comprise an orthogonal frequency division multiplexing (OFDM) symbol.

Description

BACKGROUND The present disclosure relates generally to wireless communication, and more specifically to regulating transmitter output power. In an electronic device, a transmitter may be coupled to one or more antennas to enable the electronic device to both transmit wireless signals. In some communication applications, the transmit power level of the transmitter may be adjusted (e.g., switched from a low power mode to a high power mode or vice versa) repeatedly over a short time period (e.g., with each subsequent transmitted symbol) to output a transmission signal at a desired power. However, if the power level is not switched to a desired power level within an interval between a symbol and the subsequent symbol, the transmission signal may be distorted. SUMMARY A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. In one embodiment, a transmitter includes a mixer that may output a compensated signal based on an input signal and a first compensation signal; a power amplifier electrically coupled to the mixer, where the power amplifier may amplify the compensated signal to generate an amplified signal; and a signal generator electrically coupled to the power amplifier on a feedback path of the transmitter, where the signal generator may output a second compensation signal based on a deviation in gain of the compensated signal. In another embodiment, a method may include 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 first gain compensation signal to the low power symbol of the transmit signal to reduce a gain associated with the low power symbol to generate a compensated transmit signal; generating a second gain compensation signal based on a deviation of the gain; and applying the second gain compensation signal to a subsequent symbol of the transmit signal. In yet another embodiment, a tangible, non-transitory, computer-readable medium may include machine-readable instruction, wherein the instruction may 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 first gain compensation signal reduce a gain associated with the low power symbol to generate a compensated signal; generate a second gain compensation signal based on a deviation of the gain; and apply the second gain compensation signal to the transmit signal during transmission of a subsequent low power symbol. Various refinements of the features noted above may exist in relation to various aspects of the present disclosure. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. The brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings described below in which like numerals refer to like parts. FIG. 1 is a block diagram of an electronic device, according to embodiments of the present disclosure; FIG. 2 is a functional diagram of the electronic device of FIG. 1, according to embodiments of the present disclosure; FIG. 3 is a schematic diagram of a transmitter of the electronic device of FIG. 1, according to embodiments of the present disclosure; FIG. 4 is a timing diagram illustrating a gain increase of the power amplifier and a power level profile associated with a transmitted signal; FIG. 5 is a timing diagram illustrating a compensation signal that may be applied to a transmitted signal to counteract a gain drift in a low power symbol, according to embodiments of the present disclosure; FIG. 6 a block diagram illustrating insertion of the compensation signal into a transmit chain of the transmitter of FIG. 3 to compensate for gain drift, according to embodiments of the present disclosure; FIG. 7 is a flowchart of a method for transitioning from a low power symbol to a high power symbol and applying the compensation signal to mitigate or eliminate a gain increase during transmission of the low power symbol, acco