System and method for digital memorized predistortion for wireless communication
First Claim
1. A method of operating a power amplifier, the method comprising:
- initializing the power amplifier;
performing a training phase comprising;
establishing pre-computed distortion contributions based on pre-compensation training feedback signals representative of output of the power amplifier; and
storing the pre-computed distortion contributions in a lookup table; and
performing an operating phase comprising;
switching a controller off to disconnect signal representative of the output of the power amplifier;
accepting an original value that reflects information to be communicated;
generating a digital lookup table key based on the original value;
retrieving from the lookup table, using the digital lookup table key, a corresponding pre-computed distortion contribution for the original value;
distorting the original value based on the corresponding pre-computed distortion contribution to obtain a distorted value to pre-compensate for the nonlinear characteristics of the power amplifier; and
wirelessly transmitting a pre-distorted signal based on the distorted value.
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Abstract
A power amplifier system includes an input operable to receive an original value that reflects information to be communicated and an address data former operable to generate a digital lookup table key. The power amplifier system also includes a predistortion lookup table coupled to the address data former and a power amplifier having an output and coupled to the predistortion lookup table. The power amplifier system further includes a feedback loop providing a signal associated with the output of the power amplifier to the predistortion lookup table and a switch disposed in the feedback loop and operable to disconnect the predistortion lookup table from the output of the power amplifier.
156 Citations
20 Claims
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1. A method of operating a power amplifier, the method comprising:
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initializing the power amplifier; performing a training phase comprising; establishing pre-computed distortion contributions based on pre-compensation training feedback signals representative of output of the power amplifier; and storing the pre-computed distortion contributions in a lookup table; and performing an operating phase comprising; switching a controller off to disconnect signal representative of the output of the power amplifier; accepting an original value that reflects information to be communicated; generating a digital lookup table key based on the original value; retrieving from the lookup table, using the digital lookup table key, a corresponding pre-computed distortion contribution for the original value; distorting the original value based on the corresponding pre-computed distortion contribution to obtain a distorted value to pre-compensate for the nonlinear characteristics of the power amplifier; and wirelessly transmitting a pre-distorted signal based on the distorted value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of operating a power amplifier of a mobile handset, the method comprising:
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powering on the mobile handset; populating a lookup table with pre-computed distortion contributions; switching off a controller coupled to feedback signals associated with the power amplifier; accepting an original value that reflects information to be communicated; generating a digital lookup table key based on the original value; retrieving from the lookup table, using the digital lookup table key, a corresponding pre-computed distortion contribution for the original value; distorting the original value based on the corresponding pre-computed distortion contribution to obtain a distorted value to pre-compensate for the nonlinear characteristics of the power amplifier; and wirelessly transmitting a pre-distorted signal based on the distorted value. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A power amplifier system comprising:
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an input operable to receive an original value that reflects information to be communicated; an address data former operable to generate a digital lookup table key; a predistortion lookup table coupled to the address data former; a linearity and time delay table coupled to the address data former; a power amplifier having an output and coupled to the predistortion lookup table; a feedback loop providing a signal associated with the output of the power amplifier to the predistortion lookup table, wherein the feedback loop and the output of the linearity and time delay table is configured to adaptively update the predistortion lookup table; and a switch disposed in the feedback loop and operable to disconnect the predistortion lookup table from the output of the power amplifier. - View Dependent Claims (17, 18, 19, 20)
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Specification