Rational Function Based Model for the Joint Mitigation of I/Q Imbalance and PA Nonlinearity

Aziz, Mohsin; Rawat, Meenakshi; Ghannouchi, Fadhel M.

doi:10.1109/lmwc.2013.2247751

Cited by 20 publications

(13 citation statements)

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“…Meanwhile, the popular transmitter joint compensation model proposed in the reported literature is used for the sparse model performance comparison. These popular models are (a) The PH model; (b) The rational function based model; (c) The conjugate generalized memory polynomial (GMP) model. The GMP model structure can be constructed with the different P,M,G parameters proposed in Ref.…”

Section: Simulation and Experimental Resultsmentioning

confidence: 99%

“…This method is based on an extended parallel Hammerstein (PH) structure, allowing easy estimation of DPD parameters with one‐step linear least square techniques. Based on this conjugate‐polynomial–based joint compensation approach, some similar approaches are studied extensively for the joint compensation of transmitter impairments . For example, Ref.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Ref. proposed a novel rational‐function–based conjugate model for jointly alleviating the PA nonlinearity and I/Q imperfection impairments. However, these conjugate polynomial‐based approaches have some shortcomings for joint compensation of transmitter impairments.…”

Section: Introductionmentioning

confidence: 99%

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A simplified adaptive sparse digital pre‐distorter for joint mitigation of frequency‐dependent transmitter impairments

Yao

Jin

et al. 2019

Int J RF Microw Comput Aided Eng

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The interplay between the unavoidable various nonlinearities of the direct conversion transmitter, such as local oscillator leakage, power amplifier (PA) nonlinearities, and in-phase and quadrature (I/Q) branch imbalance, and so forth will degrade the communication system performance seriously. To overcome these nonlinear interactive effects, an accurate adaptive sparse behavioral model is proposed for the joint compensation of the transmitter impairments in this article. First, a three-input nonlinear joint compensation model, which is composed of the nonlinear frequency-dependent cross terms between the I and Q branches as well as the magnitudes of the input signal, is developed.Second, to prune the redundant terms and reduce the computational complexity of the full three-input model, an efficient robust quasi-newton-based adaptive greedy algorithm is developed. To verify the performance of the proposed method, the different imperfect transmitters based on single-device GaN Class-F PA and GaN Doherty PA are used for experimental verification and analysis.Experiment results show that the proposed method can efficiently construct a sparse joint compensation model with improved modeling and distortion mitigation capability than the reported I/Q imbalance model, where nonlinear distortion and I/Q imbalance characteristics in the transmitter can be almost completely removed.

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Section: Simulation and Experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A simplified adaptive sparse digital pre‐distorter for joint mitigation of frequency‐dependent transmitter impairments

Yao

Jin

et al. 2019

Int J RF Microw Comput Aided Eng

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“…Apparently, in the literature, several models such as, Volterra series-based model, neural network-based models, and variations of memory polynomial models, have been proposed, which successfully model and mitigate the impairments introduced by modulator and power amplifiers [13,14,15,16,17,18]. However, this comes at the cost of complexity and higher processing rates.…”

Section: Introductionmentioning

confidence: 99%

Forward Behavioral Modeling of a Three-Way Amplitude Modulator-Based Transmitter Using an Augmented Memory Polynomial

Chatrath

Aziz

Helaoui

2018

Sensors

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Reconfigurable and multi-standard RF front-ends for wireless communication and sensor networks have gained importance as building blocks for the Internet of Things. Simpler and highly-efficient transmitter architectures, which can transmit better quality signals with reduced impairments, are an important step in this direction. In this regard, mixer-less transmitter architecture, namely, the three-way amplitude modulator-based transmitter, avoids the use of imperfect mixers and frequency up-converters, and their resulting distortions, leading to an improved signal quality. In this work, an augmented memory polynomial-based model for the behavioral modeling of such mixer-less transmitter architecture is proposed. Extensive simulations and measurements have been carried out in order to validate the accuracy of the proposed modeling strategy. The performance of the proposed model is evaluated using normalized mean square error (NMSE) for long-term evolution (LTE) signals. NMSE for a LTE signal of 1.4 MHz bandwidth with 100,000 samples for digital combining and analog combining are recorded as −36.41 dB and −36.9 dB, respectively. Similarly, for a 5 MHz signal the proposed models achieves −31.93 dB and −32.08 dB NMSE using digital and analog combining, respectively. For further validation of the proposed model, amplitude-to-amplitude (AM-AM), amplitude-to-phase (AM-PM), and the spectral response of the modeled and measured data are plotted, reasonably meeting the desired modeling criteria.

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“…Based on this joint compensation technique, the conjugate polynomial based model are studied extensively for compensate the frequency-dependent I/Q imbalance impairments [14]- [18]. For example, a rational function based conjugate model for the joint alleviation of PA nonlinearity effects and I/Q imbalance has been proposed in [19]. However, these conjugate polynomial based methods have their shortcomings.…”

mentioning

confidence: 99%

An Accurate Three-Input Nonlinear Model for Joint Compensation of Frequency-Dependent I/Q Imbalance and Power Amplifier Distortion

Yao

Jin

et al. 2019

IEEE Access

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The analog front of the direct conversion transmitter suffers from the effects of various unavoidable nonlinearities, such as local oscillator (LO) leakage, power amplifier (PA) nonlinearities, and in-phase and quadrature (I/Q) branch amplitude and phase imbalance, etc. To overcome these nonlinear effects, an accurate three-input nonlinear model is proposed for joint compensation of frequency-dependent I/Q imbalance and PA nonlinear distortion in this paper. The proposed nonlinear model is an augmented version of the modulator I/Q imbalance compensation model, where the magnitudes of the input signal are included as the model input, and a three-input nonlinear compensation model with linear parameters is developed. The advantage of the proposed model is that the augmented envelope-dependent terms can produce the basis function sets for compensating the PA nonlinear distortions in the transmitter. Furthermore, the computational complexity of the proposed model is analyzed in detail for practical digital implementation. To verify the validity of the proposed model, the imperfect transmitters based on singledevice gallium nitride (GaN) PA and GaN Doherty PA, which are driven by different communication signals, are used for experimental verification and analysis. The experimental results show that the proposed model is able to give improved modeling and distortion mitigation capability than the other reported I/Q imbalance compensation methods when the effects of I/Q imbalance and nonlinear characteristics of PA are considered together.INDEX TERMS Broadband, power amplifier (PA), I/Q imbalance, digital predistortion (DPD), memory polynomial, volterra series. I. INTRODUCTIONWith the rapid development and worldwide deployment of the fourth generation (4G) and international mobile telecommunication-advanced (IMT-A) system, the growing demands for various multimedia and personal wireless communication services require the development the sophisticated transceiver technologies to support high data rate and high system capacity over limited spectral resources [1]-[3]. The implementation challenge in building such compact and low-cost radio transceivers for future wirelessThe associate editor coordinating the review of this manuscript and approving it for publication was Wenchi Cheng . communication systems are continuously growing, which is primarily due to the use of the high order wideband modulation signals with increased peak-to-average power ratio (PAPR). Meanwhile, to keep the overall implementation costs and size feasible of radio transceivers, the simplified radio architectures and low-cost radio frequency (RF) circuits are typically used, which in turn implies that the various nonideal characteristics in the used analog front, such as in-phase/quadrature (I/Q) imbalance, power amplifier (PA) nonlinear distortion, and local oscillator (LO) leakage. etc, are expected to play a critical role in the future wireless communication system [4]-[8]. The serious performance degrading phenomena arised from these interactions...

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Rational Function Based Model for the Joint Mitigation of I/Q Imbalance and PA Nonlinearity

Cited by 20 publications

References 7 publications

A simplified adaptive sparse digital pre‐distorter for joint mitigation of frequency‐dependent transmitter impairments

A simplified adaptive sparse digital pre‐distorter for joint mitigation of frequency‐dependent transmitter impairments

Forward Behavioral Modeling of a Three-Way Amplitude Modulator-Based Transmitter Using an Augmented Memory Polynomial

An Accurate Three-Input Nonlinear Model for Joint Compensation of Frequency-Dependent I/Q Imbalance and Power Amplifier Distortion

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