80 results about "Memory polynomial" patented technology

Non-linear interference cancellation techniques are provided for wireless transceivers. Non-linear reduction of interference of a transmit signal on a received signal in a transceiver device, comprises applying the transmit signal to a first non-linear system; applying the received signal to a second non-linear system; and subtracting an output of the first non-linear system output from an output of second non-linear system output to produce an interference mitigated received signal. The first non-linear system and/or the second non-linear system can be to implemented using one or more of a Volterra series and a Generalized Memory Polynomial Model. System parameters of the first non-linear system and/or the second non-linear system are adapted to reduce a power of the interference mitigated received signal.

A power amplifier system including a composite digital predistorter (DPD) ensuring optimized linearity for the power amplifier is described. In this system, a digital-to-analog converter (DAC), an analog filter, a first mixer, and the power amplifier are serially coupled to the composite DPD. A second mixer, a receive gain block, and an analog-to-digital converter (ADC) are serially coupled to the output of the power amplifier. A DPD training component is coupled between the inputs of the composite DPD and the ADC. The composite DPD includes a memory-based DPD, e.g., a memory polynomial (MP) DPD, a memoryless-linearizing DPD, e.g., a look-up table (LUT) DPD, and two multiplexers.

The augmented twin nonlinear two-box modeling and predistortion method for power amplifiers and transmitters provides power amplifier distortion modeling and predistortion linearization. A memoryless nonlinearity is combined with a memory polynomial function that includes cross-terms. The method can utilize an augmented forward twin-nonlinear two-box model, an augmented reverse twin-nonlinear two-box model, or alternatively, an augmented parallel twin-nonlinear two-box model. The present two-box models are validated in modeling and predistortion applications. Measurement results demonstrate the superiority of the present two-box models with respect to conventional state of the art models. The present two-box models lead to better accuracy with reduced complexity.

The invention relates to the technology of digital pre-distortion, provides a novel digital pre-distortion structure, and achieves a good effect in the linearization of a power amplifier. According to the technical scheme, a memory polynomial digital pre-distortion method based on a piecewise linear function includes: the input of a pre-distortion module is y(n)/G, and the output is the conjugate of z(n), and G is the gain of the power amplifier. An input signal is x(n), the input signal passes through a structure which is the same with the pre-distortion module to generate an output signal z(n), e(n)=z(n)-the conjugate of z(n), e(n) is minimized by employing the recursive least squares algorithm iteration, and the signal is linearly amplified. The method is mainly applied to linearization occasions of the power amplifiers.

The invention relates to a digital pre-distortion processing method and device for a power amplifier. The digital pre-distortion processing device for the power amplifier comprises a pre-distortion module, a forward direction data collection module, a feedback data collection module, a microprocessor module and a control module. According to the digital pre-distortion processing method for the power amplifier, forward direction data entering the pre-distortion module and feedback data amplified by the power amplifier and fed back through a same data source channel after a peak subsides are collected; parameters of a memory polynomial in the pre-distortion module are computed in the RLS method based on the QR factorization; after coefficient computation is finished, the results are updated into the parameters of the memory polynomial in the pre-distortion module in a parallel mode; signals processed by a peak-subsiding module enter the pre-distortion module, memory polynomial computation is conducted, and pre-distortion processing of eliminating nonlinear effect of the power amplifier is conducted; circulating collection and iterative computations enable digital pre-distortion processing to be in a restrain state. Timeliness of a system is improved and resource consumption of the whole system is reduced on the whole, abnormal condition can be processed, and system stability is improved.

A system and method for linearizing a power amplifier using digital predistortion technique is provided including processing circuitry, the processing circuitry configured to apply a digital predistortion function based on a weighted static polynomial function, a weighted dynamic polynomial function and a threshold parameter which splits the nonlinear transfer characteristics of the device under test into a region where the static nonlinearity predominates and a region where the dynamic distortions predominate.

An electronic device includes a nonlinear power amplifier, a predistortion coefficient calculator, and a memory polynomial predistortion filter coupled to the nonlinear power amplifier and to the predistortion coefficient calculator. The memory polynomial predistortion filter may include a plurality of finite impulse response (FIR) filter stages, and a summer coupled to the plurality of FIR filter stages. The FIR filter stages may functionally operate in parallel or may include a series of FIR filters coupled in parallel.

The invention relates to a digital predistortion method of jointly compensating for IQ imbalance and PA non-linearity. Comprehensively considering the requirement of jointly compensating for IQ imbalance and PA non-linearity, based on a GMP (Generalized Memory Polynomial)-based traditional digital predistortion model, the method further considers I/Q imbalance influence, and simultaneously completes I/Q imbalance non-linearity and power amplification non-linearity compensation, thereby eliminating main non-linearity in a transmitter.

The invention discloses a method, equipment and a system for adjusting the linear performance of predistortion. The method mainly comprises the steps that a system of linear equations based on a memory polynomial model is constructed according to an input signal z(n) and an output signal y(n) of a radio-frequency power amplifier, and after the system of linear equations is converted, an expression of a predistortion factor a comprising R_uu is obtained; the process of determining the predistortion factor a is converted to a process of determining a characteristic value matrix S and a characteristic vector matrix V of the R_uu, so as to simplify the computational complexity; in the process of determining the characteristic value matrix S and the characteristic vector matrix V, the dimensionality for conducting matrix operations is lower, and storage space needed by the operations is less; and finally, the determined characteristic value matrix S and characteristic vector matrix V of the R_uu are plugged into the expression of the predistortion factor a to obtain the predistortion factor. The predistortion factor a obtained in such a way has higher stability, so the linear adjusting performance of the predistortion is also improved to some extent.

The invention provides a mixed double-frequency digital pre-distortion model method based on the DDR. The method includes the following steps that a concurrent double-frequency DPD system based on indirect learning is built; an operation sequence is optimized, a one-dimensional LUT achievement model of the 2D-MP is obtained, a one-dimensional LUT achievement model of 2D-MMP is derived, and then aone-dimensional LUT high-frequency concurrent double-frequency DPD achievement scheme and a model are provided; a dynamic deviation function is substituted into a one-order model of the DDR, and a discrete equivalent baseband expression of the one-order DDR model is obtained and extended to be in a synchronic double-frequency mode; a two-dimensional memory polynomial model same-order envelope cross term is introduced, and a new model and a one-dimensional LUT achievement method of the model in an FPGA are obtained. According to the method, the modeling accuracy and the linearization performance better than a simplified two-dimensional memory polynomial model and a traditional DDR model can be obtained; meanwhile, the advantage that achievement can be conveniently conducted through a one-dimensional lookup table is kept, the new model has a good level in the aspects of performance and complexity, and the method is suitable for practical system applying.

The digital predistortion system and method with extended correction bandwidth includes a predistortion system that uses a two-box architecture based on the cascade of a memory polynomial followed by a memoryless predistortion function. The memoryless predistorter is identified offline and used to perform a coarse linearization which cancels out most of the static nonlinearity of the device under test allowing for a reduced observation bandwidth for the synthesis of the memory polynomial predistortion sub-function.

The behavioral model and predistorter for modeling and reducing nonlinear effects in power amplifiers addresses the model size estimation problem. The GMP model is replaced by the hybrid memory polynomial/envelope memory polynomial (HMEM) model within a twin nonlinear two-box structure to reduce the number of variables involved in the model size estimation problem, without compromising model accuracy and digital predistorter performance. A sequential approach is presented to efficiently estimate the model size. Experimental validation is carried out to evaluate the performance of the size estimation and the accuracy of the HMEM-based twin-nonlinear two-box model with respect to that of the GMP-based twin-nonlinear two-box model.

The invention discloses a pre-distortion method for a power amplifier. The pre-distortion method includes the steps that transmitting signals x(k) are received; the transmitting signals x(k) are substituted into a pre-distortion relational expression which is established according to the characteristics of the power amplifier and is based on a memory polynomial, the transmitting signals x(k) are subjected to pre-distortion in combination with a lookup table, pre-distorted transmitting signals y(k) are obtained, and the pre-distorted transmitting signals y(k) are sent to the power amplifier for power amplification and output. It is thus clear that before the transmitting signals x(k) are sent to the power amplifier, the transmitting signals x(k) are subjected to pre-distortion through the pre-distortion relational expression which is established according to the characteristics of the power amplifier and is based on the memory polynomial, distortion caused by non-linearity of the power amplifier and generated when the pre-distorted transmitting signals y(k) pass through the power amplifier is offset, optimal performance transmission of the transmitting signals x(k) is guaranteed, radio frequency transmitting efficiency is improved, and the application range is wide. The invention further discloses a pre-distortion device for the power amplifier and a radio frequency system.

The memory polynomial based digital predistorter utilizes a cluster-based particle swarm optimization (PSO) technique and has an embedded model-size estimator. The PSO technique and model-size estimator efficiently find the dimensions and accurately estimate the coefficients of the memory polynomial based digital predistorter for improved linearity of a power amplifier.

The invention discloses a digital pre-distortion (DPD) processing method for a multi-mode RRU. The method comprises the following steps: a DPD processing module carries out time delay calculation according to captured forward downlink signals and captured feedback signals, and carries out alignment processing on the forward downlink signals and the feedback signals; matrix modeling is carried outon the forward downlink signals and the feedback signals which are aligned through a memory polynomial model, so that a pre-distortion coefficient is calculated; and the pre-distortion coefficient isused on the forward downlink signals, and pre-distorted downlink signals are output to a power amplifier, so that the linearity of the power amplifier and the demodulation performance of multi-mode signals can be improved. The method disclosed by the invention has the following beneficial effects: non-linear distortion of the multi-mode signals can be calibrated; and compared with the prior art, the method has the advantages that the DPD processing module adopts the multi-mode DPD algorithm, so that single-mode broadband signals, single-mode narrowband signals and multi-mode broadband signalscan be processed.

The invention discloses a digital pre-distortion processing method based on a memory and cross memory polynomial model. The method includes: carrying out modulo operation on each input baseband signalto obtain the amplitude corresponding to each input baseband signal; delaying each input baseband signal and solving the modulus to obtain the amplitude of a delayed signal, wherein the amplitude ofeach input baseband signal and the amplitude of the delayed signal respectively pass through an address mapping unit and then are used as an address index of a lookup table to look up a correspondingcrossed item pre-distortion coefficient and a corresponding non-crossed item pre-distortion coefficient; and establishing a memory and cross memory polynomial model, multiplying the input signals after time delay alignment by the corresponding pre-distortion coefficients and amplitudes, accumulating the multiplied input signals to serve as signal output after pre-distortion processing, and performing digital pre-distortion processing on each input baseband signal according to the memory and cross memory polynomial model to obtain output baseband signals. According to the invention, the compromise of modeling precision and calculation complexity can be realized.

The invention belongs to the technical field of adaptive digital pre-distortion and discloses a system and a method for improving short-wave digital pre-distortion performance. For the characteristicof narrow bandwidth of short-wave signals, a weak nonlinear filter of an FIR filter is integrated to overcome a memory effect, and a memory polynomial model is integrated, so that pre-distortion parameter extraction can be carried out with higher integrating degree, parameters more conforming to actual characteristics of the power amplifier are obtained, the performance of a digital pre-distortionsystem is improved, and the linearity and the power amplifier efficiency of the radio frequency power amplifier are improved.