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;
establishing pre-computed distortion contributions by training based on pre-compensation training feedback signals representative of output of the power amplifier;
storing the pre-computed distortion contributions in a lookup table;
maintaining the lookup table;
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;
wherein establishing pre-computed distortion contributions comprises;
establishing reference information by training based on reference training feedback signals via feedback channels, the reference training feedback signals being representative of the output of the power amplifier; and
storing the reference information in a reference table; and
wherein maintaining the lookup table comprises refraining, once the pre-computed distortion contributions are established, for at least one entire telephone conversation, from further training to establish the pre-computed distortion contributions or the reference information.
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Accused Products
Abstract
An embodiment of the invention is a system for signal processing in preparation for wireless transmission, the wireless transmission being from a portable wireless communication device and including use of a power amplifier having nonlinear characteristics. The system includes memory for storing digitally-indexed information. The digitally-indexed information models nonlinear characteristics of the power amplifier, and the digitally-indexed information is stored prior to processing of a first signal that reflects information to be communicated. The system further includes first logic, configured to accept the first signal and to retrieve, based on the first signal, a portion of the digitally-indexed information stored in the memory, and second logic, configured to generate a second signal based on the portion of the digitally-accessed information and on the first signal. The second signal pre-compensates for the nonlinear characteristics of the power amplifier, and the second signal is for wireless transmission based on the second signal.
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Citations
14 Claims
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1. A method of operating a power amplifier, the method comprising:
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initializing the power amplifier; establishing pre-computed distortion contributions by training based on pre-compensation training feedback signals representative of output of the power amplifier; storing the pre-computed distortion contributions in a lookup table; maintaining the lookup table; 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; wherein establishing pre-computed distortion contributions comprises; establishing reference information by training based on reference training feedback signals via feedback channels, the reference training feedback signals being representative of the output of the power amplifier; and storing the reference information in a reference table; and wherein maintaining the lookup table comprises refraining, once the pre-computed distortion contributions are established, for at least one entire telephone conversation, from further training to establish the pre-computed distortion contributions or the reference information. - View Dependent Claims (2, 3, 4, 6, 7)
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5. A method of operating a power amplifier, the method comprising:
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initializing the power amplifier; establishing pre-computed distortion contributions by training based on pre-compensation training feedback signals representative of output of the power amplifier; storing the pre-computed distortion contributions in a lookup table; maintaining the lookup table; 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; wherein establishing pre-computed distortion contributions comprises; establishing reference information by training based on reference training feedback signals via feedback channels, the reference training feedback signals being representative of the output of the power amplifier; and storing the reference information in a reference table; and wherein maintaining the lookup table comprises refraining, once the pre-computed distortions contributions are established, for at least one day, from further training to establish the pre-computed distortion contributions or the reference information.
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8. A method of operating a power amplifier for wireless transmission of signals, the method comprising:
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maintaining a lookup table that contains pre-computed distortion contributions; 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; wherein maintaining the lookup table comprises; establishing pre-computed distortion contributions by training based on pre-compensation training feedback signals, the pre-compensation feedback signals being representative of output of the power amplifier; storing the pre-computed distortion contributions in a lookup table; and refraining, once the pre-computed distortion contributions are established, for at least one entire communication session, from further training to establish the pre-computed distortion contributions or the reference information; and wherein establishing pre-computed distortion contributions comprises; establishing reference information by training based on reference training feedback signals via feedback channels, the reference training feedback signals being representative of the output of the power amplifier; and storing the reference information in a reference table. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of operating a power amplifier for wireless transmission of signals, the method comprising:
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maintaining a lookup table that contains pre-computed distortion contributions; 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; wherein maintaining the lookup table comprises; establishing pre-computed distortion contributions by training based on pre-compensation training feedback signals, the pre-compensation feedback signals being representative of output of the power amplifier; storing the pre-computed distortion contributions in a lookup table; and refraining, once the pre-computed distortion contributions are established, for at least one day, from further training to establish the pre-computed distortion contributions or the reference information; and wherein establishing pre-computed distortion contributions comprises; establishing reference information by training based on reference training feedback signals via feedback channels, the reference training feedback signals being representative of the output of the power amplifier; and storing the reference information in a reference table.
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Specification