Digital Predistortion for nonlinear RF power amplifiers
First Claim
1. A system, comprising:
- processor electronics configured to produce a digital transmit signal;
a first convertor to convert the digital transmit signal to an analog transmit signal;
a power amplifier to amplify the analog transmit signal, wherein the power amplifier has one or more nonlinear characteristics;
receiver circuitry to receive an analog receive signal in one of an operational mode or a predistortion training mode;
a second convertor to convert the analog receive signal to a digital receive signal; and
a receive filter coupled between the receiver circuitry and the second convertor,wherein the processor electronics are configured to perform operations comprisingcausing the receive filter to operate at a wider bandwidth during the predistortion training mode;
causing the receiver circuitry, in the predistortion training mode, to receive the amplified analog transmit signal as the analog receive signal,sampling the digital transmit signal to produce transmit samples,sampling the digital receive signal to produce receive samples,determining a synchronization offset value to align the transmit samples with the receive samples,determining one or more power normalization parameter values to normalize a power of the digital receive signal with respect to the digital transmit signal,estimating predistortion parameter values using information comprising the transmit samples, the receive samples, the synchronization offset value, and the one or more power normalization parameter values, andusing the predistortion parameter values to predistort digital signals to compensate for the one or more nonlinear characteristics of the power amplifier.
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Accused Products
Abstract
Systems and techniques relating to wireless communications are described. A described technique includes generating a digital transmit signal, receiving a digital receive signal, storing signal samples, the signal samples including transmit samples based on the digital transmit signal and receive samples based on the digital receive signal, causing, in a predistortion training mode, the digital receive signal to be based on an amplified analog version of the digital transmit signal, where the amplified analog version is produced by a power amplifier having one or more nonlinear characteristics, determining a synchronization offset value to align the transmit samples with the receive samples, determining one or more power normalization parameter values to normalize a power of the digital receive signal with respect to the digital transmit signal, estimating predistortion parameter values, and using the predistortion parameter values to predistort digital signals to compensate for the one or more nonlinear characteristics of the power amplifier. Estimating predistortion parameter values can include using information comprising the transmit samples, the receive samples, the synchronization offset value, and the one or more power normalization parameter values.
86 Citations
20 Claims
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1. A system, comprising:
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processor electronics configured to produce a digital transmit signal; a first convertor to convert the digital transmit signal to an analog transmit signal; a power amplifier to amplify the analog transmit signal, wherein the power amplifier has one or more nonlinear characteristics; receiver circuitry to receive an analog receive signal in one of an operational mode or a predistortion training mode; a second convertor to convert the analog receive signal to a digital receive signal; and a receive filter coupled between the receiver circuitry and the second convertor, wherein the processor electronics are configured to perform operations comprising causing the receive filter to operate at a wider bandwidth during the predistortion training mode; causing the receiver circuitry, in the predistortion training mode, to receive the amplified analog transmit signal as the analog receive signal, sampling the digital transmit signal to produce transmit samples, sampling the digital receive signal to produce receive samples, determining a synchronization offset value to align the transmit samples with the receive samples, determining one or more power normalization parameter values to normalize a power of the digital receive signal with respect to the digital transmit signal, estimating predistortion parameter values using information comprising the transmit samples, the receive samples, the synchronization offset value, and the one or more power normalization parameter values, and using the predistortion parameter values to predistort digital signals to compensate for the one or more nonlinear characteristics of the power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus, comprising:
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processor electronics configured to (i) produce a digital transmit signal and (ii) receive a digital receive signal via circuitry that includes a receive filter; and a memory to store signal samples, the signal samples including (i) transmit samples based on the digital transmit signal and (ii) receive samples based on the digital receive signal, wherein the processor electronics are configured to perform operations comprising causing, in a predistortion training mode, the digital receive signal to be based on an amplified analog version of the digital transmit signal, wherein the amplified analog version is produced by a power amplifier having one or more nonlinear characteristics, causing the receive filter to operate at a wider bandwidth during the predistortion training mode, determining a synchronization offset value to align the transmit samples with the receive samples, determining one or more power normalization parameter values to normalize a power of the digital receive signal with respect to the digital transmit signal, estimating predistortion parameter values using information comprising the transmit samples, the receive samples, the synchronization offset value, and the one or more power normalization parameter values, and using the predistortion parameter values to predistort digital signals to compensate for the one or more nonlinear characteristics of the power amplifier. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method, comprising:
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generating a digital transmit signal; receiving a digital receive signal via circuitry that includes a receive filter; storing signal samples, the signal samples including transmit samples based on the digital transmit signal and receive samples based on the digital receive signal; causing, in a predistortion training mode, the digital receive signal to be based on an amplified analog version of the digital transmit signal, wherein the amplified analog version is produced by a power amplifier having one or more nonlinear characteristics; causing the receive filter to operate at a wider bandwidth during the predistortion training mode; determining a synchronization offset value to align the transmit samples with the receive samples; determining one or more power normalization parameter values to normalize a power of the digital receive signal with respect to the digital transmit signal; estimating predistortion parameter values using information comprising the transmit samples, the receive samples, the synchronization offset value, and the one or more power normalization parameter values; and using the predistortion parameter values to predistort digital signals to compensate for the one or more nonlinear characteristics of the power amplifier. - View Dependent Claims (17, 18, 19, 20)
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Specification