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公开(公告)号：US10931320B2
公开(公告)日：2021-02-23
申请号：US17005944
申请日：2020-08-28
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Kevin Chuang , Yan Li , Zohaib Mahmood , Helen H. Kim
Abstract: Disclosed are digital predistortion implementations, including a method that includes obtaining a first set of digital predistortion (DPD) non-linear functions for controlling operation of a digital predistorter of a wireless device operating on a received at least one input signal directed to a power amplification system comprising a transmit chain with at least one power amplifier that produces output with non-linear distortions. The method further includes determining an expanded set of DPD non-linear functions comprising the first set of DPD non-linear functions and additional one or more sets of DPD non-linear functions derived based on the first set of DPD non-linear functions and on operating condition parameters associated with operation of the wireless device, and configuring the digital predistorter with DPD coefficients determined for the expanded set of the DPD non-linear functions based on observed samples of the transmit chain responsive to the at least one input signal.
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公开(公告)号：US20200028476A1
公开(公告)日：2020-01-23
申请号：US16487969
申请日：2018-02-23
Applicant: NanoSemi, Inc
Inventor： Helen H. Kim , Alexandre Megretski , Yan Li , Kevin Chuang , Zohaib Mahmood , Yanyu Huang
Abstract: Disclosed are methods, systems, devices, apparatus, media, design structures, and other implementations, including a method for digital predistortion of multiband signals that includes receiving a plurality of input signals respectively associated with multiple radio frequency (RF) bands, with the plurality of input signals occupying an input frequency span corresponding to a difference between a maximum frequency in a highest of the multiple RF bands and a minimum frequency in a lowest of the multiple RF bands. The method further includes frequency shifting at least one signal from the plurality of input signals to produce condensed shifted signals, each corresponding to a respective one of the plurality of input signals, occupying a condensed frequency span smaller than the input frequency span, and processing the condensed shifted signals, including applying digital predistortion to the condensed shifted signals.
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公开(公告)号：US20190363742A1
公开(公告)日：2019-11-28
申请号：US16422448
申请日：2019-05-24
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Kevin Chuang , Yan Li , Zohaib Mahmood , Helen H. Kim
Abstract: Disclosed are digital predistortion implementations, including a method that includes collecting data for a wireless device with a transmit chain that includes at least one power amplifier that produces output with non-linear distortions, the data including data records that each includes input signal data and corresponding output signal data for the transmit chain, and with each record being associated with a set of operating conditions values, and with a variety measure representative of an extent of distinguishability of the record from other data records. The method further includes selecting at least some of the data records according to a variety criterion computed based on the variety measure for each record, computing, based on the selected records, digital predistortion parameters used to control a digital predistorter of the wireless device, and applying the digital predistorter, configured with the computed digital predistortion parameters, to subsequent input signals.
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公开(公告)号：US11171614B2
公开(公告)日：2021-11-09
申请号：US16865715
申请日：2020-05-04
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Kevin Chuang , Yan Li , Zohaib Mahmood , Helen H. Kim
Abstract: A pre-distorter that both accurately compensates for the non-linearities of a radio frequency transmit chain, and that imposes as few computation requirements in terms of arithmetic operations, uses a diverse set of real-valued signals that are derived from separate band signals that make up the input signal. The derived real signals are passed through configurable non-linear transformations, which may be adapted during operation, and which may be efficiently implemented using lookup tables. The outputs of the non-linear transformations serve as gain terms for a set of complex signals, which are functions of the input, and which are summed to compute the pre-distorted signal. A small set of the complex signals and derived real signals may be selected for a particular system to match the classes of non-linearities exhibited by the system, thereby providing further computational savings, and reducing complexity of adapting the pre-distortion through adapting of the non-linear transformations.
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公开(公告)号：US10992326B1
公开(公告)日：2021-04-27
申请号：US16877606
申请日：2020-05-19
Applicant: NanoSemi, Inc
Inventor： Alexandre Megretski , Yan Li , Zohaib Mahmood , Kevin Chuang , Helen H. Kim
IPC: H04B1/04
Abstract: Disclosed are implementations, including a method comprising selecting a location of a selection buffer (that stores observed output samples produced by a signal chain) according to a pseudo-random buffer selection process, and accessing at least one observed output sample generated in response to corresponding input samples (to the system) and/or intermediary samples (outputs of a digital compensator) produced by a compensator of the system. The method further includes computing an approximation of a sub-gradient value computed according to a stochastic gradient process to derive a sub-gradient of an error function representing a relationship between the observed output sample, and the input and/or intermediary samples, computing updated values for the compensator coefficients based on current values of the coefficients and the approximation of the sub-gradient value, and replacing, at a time instance determined independently of the buffer selection process, content of part or all of the selection buffer.
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Patent Agency Ranking
公开(公告)号：US10931238B2
公开(公告)日：2021-02-23
申请号：US16386755
申请日：2019-04-17
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Zohaib Mahmood , Yan Li , Kevin Chuang , Helen H. Kim , Yu-Chen Wu
Abstract: Disclosed are systems, devices, modules, methods, and other implementations, including a method for digital predistortion that includes receiving, by a digital predistorter, a first signal that depends on amplitude variations based on an input signal, u, with the variations of the first signal corresponding to time variations in non-linear characteristics of a transmit chain that includes a power amplifier. The method further includes receiving, by the digital predistorter, the input signal u, generating, by the digital predistorter, based at least in part on signals comprising the input signal u and the first signal, a digitally predistorted signal v to mitigate the non-linear behavior of the transmit chain, and providing the predistorted signal v to the transmit chain.
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公开(公告)号：US20190260402A1
公开(公告)日：2019-08-22
申请号：US16004713
申请日：2018-06-11
Applicant: NanoSemi, Inc.
Inventor： Kevin Chuang , Alexandre Megretski , Yan Li , Helen H. Kim
IPC: H04B1/04
Abstract: Disclosed are implementations, including a method for digital predistortion of multiband signals that includes receiving an input signal comprising multiple signal portions in different frequency bands, the input signal configured to be processed by a transmit chain, of a power amplification system, comprising at least a power amplifier that produces output with non-linear distortions, with the non-linear distortions of the transmit chain being represented using a set of basis functions derived according to a single-band model of the non-linear distortions. The method further includes performing digital predistortion on signal components derived from the multiple signal portions of the input signal using a reduced set of the basis functions that excludes at least some basis functions for at least some cross-terms resulting from a full expansion of the single-band model applied to the multiple signal portions, to produce a digital predistorted signal provided to the transmit chain.
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公开(公告)号：US20190260401A1
公开(公告)日：2019-08-22
申请号：US16004594
申请日：2018-06-11
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Zohaib Mahmood , Kevin Chuang , Yan Li , Helen H. Kim
Abstract: A linearization system computes a robust set of quantities characterizing a nonlinearity of a transmit chain including a power amplifier by combining a current set of quantities characterizing the nonlinearity of the transmit chain with a weighted combination of prior sets of quantities characterizing the nonlinearity of the transmit chain.
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公开(公告)号：US09564876B2
公开(公告)日：2017-02-07
申请号：US14492180
申请日：2014-09-22
Applicant: NANOSEMI, INC.
Inventor： Helen H. Kim , Alexandre Megretski , Yan Li , Kevin Chuang
CPC classification number: H03H17/0261
Abstract: Aspects and embodiments are directed to non-linear systems including a digital compensator structure, a method of digital compensation, and methods for designing digital compensator structures for analog receivers. A digital compensator is configured to substantially reduce the one or more nonlinear distortion components in the sampled digital output signal from the analog receiver to provide an output signal achieving a receiver linearity requirement for the combination of the analog receiver and a digital compensator.
Abstract translation: 方面和实施例涉及包括数字补偿器结构，数字补偿方法以及用于设计用于模拟接收机的数字补偿器结构的方法的非线性系统。 数字补偿器被配置为基本上减少来自模拟接收机的采样数字输出信号中的一个或多个非线性失真分量，以提供实现模拟接收机和数字补偿器的组合的接收机线性度要求的输出信号。
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公开(公告)号：US10763904B2
公开(公告)日：2020-09-01
申请号：US16422448
申请日：2019-05-24
Applicant: NanoSemi, Inc.
Inventor： Alexandre Megretski , Kevin Chuang , Yan Li , Zohaib Mahmood , Helen H. Kim
Abstract: Disclosed are digital predistortion implementations, including a method that includes collecting data for a wireless device with a transmit chain that includes at least one power amplifier that produces output with non-linear distortions, the data including data records that each includes input signal data and corresponding output signal data for the transmit chain, and with each record being associated with a set of operating conditions values, and with a variety measure representative of an extent of distinguishability of the record from other data records. The method further includes selecting at least some of the data records according to a variety criterion computed based on the variety measure for each record, computing, based on the selected records, digital predistortion parameters used to control a digital predistorter of the wireless device, and applying the digital predistorter, configured with the computed digital predistortion parameters, to subsequent input signals.
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