Method and apparatus for correcting inconvenient power amplifier load characteristics in an envelope tracking based system

A system for envelope tracking, comprising:

• a power amplifier configured to operate in an envelope tracking (ET) mode of operation over a transmit band;
• at least one filter configured to filter an output signal of the power amplifier;
• a first tunable matching network configured to couple to the power amplifier and to the at least one filter;
• and
• a control component configured to detect a present set of operating conditions of the power amplifier when the power amplifier operates in the ET mode of operation, wherein the control component is further configured to transmit a control signal to the first tunable matching network in response to the detected present set of operating conditions,
• wherein the first tunable matching network is further configured to adjust an impedance of the first tunable matching network in response to the transmitted control signal to optimize one or more ET characteristics of the power amplifier based at least in part on the present set of operating conditions,
• wherein the transmit band comprises two or more sub-bands, wherein a first sub-band of the two or more sub-bands comprises the present frequency, and wherein the one or more ET characteristics are optimized over the first sub-band, and
• wherein the transmit band is divided into the two or more sub-bands based at least in part on a frequency response of an input impedance of the at least one filter.

A non-transitory machine readable medium comprising instructions that, when executed, cause a User Equipment (UE) to:

• determining a first state of a tunable matching network coupled to a power amplifier that is configured to operate within a transmit band in an envelope tracking (ET) mode of operation, wherein the first state optimizes one or more ET characteristics at a first set of operating conditions of the power amplifier;
• and
• determining a second state of the tunable matching network coupled to the power amplifier that is configured to operate within the transmit band in the ET mode of operation, wherein the second state optimizes the one or more ET characteristics at a second set of operating conditions of the power amplifier,
• wherein the transmit band comprises two or more sub-bands, wherein the first set of operating conditions comprises operation of the power amplifier within a first sub-band of the two or more sub-bands, and wherein the second set of operating conditions comprises operation of the power amplifier within a second sub-band of the two or more sub-bands.