Memory predistortion in bandwidth limited envelope tracking
First Claim
1. An apparatus for compensating nonlinearities in envelope tracking (ET) used in a mobile device, the apparatus comprising:
- memory; and
processing circuitry, configured to;
filter an envelope signal representing an envelope of an input baseband signal to limit a bandwidth of the envelope signal to be less than a bandwidth of tracker circuitry;
generate a scaled replica of an output signal of the tracker circuitry based on the bandwidth-limited envelope signal;
generate a model distortion signal based on the scaled replica and the input baseband signal, the model distortion signal emulating ET linearity degradation;
generate an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, the output baseband signal being pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities; and
provide the output baseband signal to transmitter circuitry to be converted to an RF signal for transmission by the transmitter circuitry.
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Accused Products
Abstract
An apparatus compensates nonlinearities in envelope tracking (ET) used in a mobile device by limiting a bandwidth of an envelope signal representing an envelope of an input baseband signal to be less than a bandwidth of tracker circuitry, generating a scaled replica of an output signal of the tracker circuitry based on the bandwidth-limited envelope signal, and generating a model distortion signal based on the scaled replica and the input baseband signal, where the model distortion signal emulates ET linearity degradation. The apparatus is further configured to generate an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, where the output baseband signal is pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities.
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Citations
29 Claims
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1. An apparatus for compensating nonlinearities in envelope tracking (ET) used in a mobile device, the apparatus comprising:
- memory; and
processing circuitry, configured to;filter an envelope signal representing an envelope of an input baseband signal to limit a bandwidth of the envelope signal to be less than a bandwidth of tracker circuitry; generate a scaled replica of an output signal of the tracker circuitry based on the bandwidth-limited envelope signal; generate a model distortion signal based on the scaled replica and the input baseband signal, the model distortion signal emulating ET linearity degradation; generate an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, the output baseband signal being pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities; and provide the output baseband signal to transmitter circuitry to be converted to an RF signal for transmission by the transmitter circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- memory; and
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11. A method of compensating envelope tracking (ET) nonlinearities in a mobile device, the method comprising:
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filtering an envelope signal representing an envelope of an input baseband signal to limit a bandwidth of the envelope signal to be less than a bandwidth of tracker circuitry; generating a scaled replica of an output signal of the tracker circuitry based on the bandwidth-limited envelope signal; generating a model distortion signal based on the scaled replica and the input baseband signal, the model distortion signal emulating ET linearity degradation; generating an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, the output baseband signal being pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities; and providing the output baseband signal to transmitter circuitry to be converted to an RF signal for transmission by the transmitter circuitry. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a mobile device, to perform operations for compensating nonlinearities in envelope tracking (ET), the operations to configure the one or more processors to:
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filter an envelope signal representing an envelope of an input baseband signal to limit a bandwidth of the envelope signal to be less than a bandwidth of tracker circuitry; generate a scaled replica of an output signal of the tracker circuitry, the scaled replica generated based on the bandwidth-limited envelope signal; generate a model distortion signal based on the scaled replica and the input baseband signal, the model distortion signal emulating ET linearity degradation; generate an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, the output baseband signal being pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities; and provide the output baseband signal to transmitter circuitry to be converted to an RF signal for transmission by the transmitter circuitry. - View Dependent Claims (21, 22, 23, 24)
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25. An apparatus of a mobile device, the apparatus configured to compensate nonlinearities in envelope tracking (ET), the apparatus comprising:
- memory; and
processing circuitry, configured to;generate an input baseband signal; generate an envelope signal from the input baseband signal; shape the envelope signal; filter the shaped envelope signal to limit a bandwidth of the envelope signal to be less than a bandwidth of tracker circuitry; generate a scaled replica of an output signal of the tracker circuitry, the scaled replica generated based on the bandwidth-limited envelope signal; generate a model distortion signal as a ratio of the input baseband signal and the scaled replica, the model distortion signal emulating ET linearity degradation; generate an output baseband signal based on the scaled replica, the model distortion signal, and the input baseband signal, the output baseband signal being pre-distorted relative to the input baseband signal according to the scaled replica, the model distortion signal, and the input baseband signal to compensate for degradations in transmit signal quality due to ET nonlinearities; generate a radio frequency (RF) signal based on the output baseband signal; amplify the RF signal by a power amplifier having an input voltage modulated by tracker circuitry based on a conditioned representation of the scaled replica; and transmit the RF signal by RF front end circuitry and antenna. - View Dependent Claims (26, 27, 28, 29)
- memory; and
Specification