A Combined Approach to Digital Predistortion and Crest Factor Reduction for the Linearization of an RF Power Amplifier

Braithwaite, R. Neil

doi:10.1109/tmtt.2012.2222911

Cited by 35 publications

(22 citation statements)

References 16 publications

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“…Practically, the PA must not clip the signal peaks, meaning that the maximum output power of the PA must be around PAPR times larger than the average one. Crest-reduction techniques [11][12][13] can be applied to partially overcome this limit, at the cost of an increased non-linear behaviour. Figure 2 reports the efficiency of a conventional Class-AB PA along with the probability density functions of three different modulated signal, as a function of Output power Back-Off (OBO), which is the amount of output power reduction with respect to the maximum.…”

Section: Power Amplifier Design Challengesmentioning

confidence: 99%

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High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

et al. 2017

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Abstract:Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed.

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Section: Power Amplifier Design Challengesmentioning

confidence: 99%

“…All the HEPR enhancement solutions proposed so far proved to be able to handle PAPRs up to roughly 10 dB, which can be considered sufficient if used in conjunction with some digital Crest Factor Reduction (CFR) algorithm that reduces the peaks of the modulated waveform to limit its PAPR [11][12][13].…”

Section: Obomentioning

confidence: 99%

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

et al. 2017

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“…are the model parameters relative to the dth degree. Parameters in (13) can be estimated during on-line oper ation using standard least squares techniques [23]. Towards this, we consider the cost function Cb) = lu(n) -y(n)12 and formulate a least mean squares algorithm to determine the optimal 'Y.…”

Section: Adaptive Crest Factor Reductionmentioning

confidence: 99%

“…Further, the use of PAPR re duction in conjunction with signal predistortion has also been widely considered in literature. Several works propose a scheme in which PAPR reduction precedes predistortion [11,12], while [13] proposes a scheme where predistortion is followed by PAPR reduction. A different approach was recently proposed in [14], that presents a method to include PAPR control as a constraint in the estimation of the predistortion parameters.…”

Section: Introductionmentioning

confidence: 99%

Generalized direct predistortion with adaptive crest factor reduction control

Piazza

Shankar

Ottersten

2015

2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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Efficient power amplification is inherently a non linear operation that introduces unwanted interference in the amplified signal. Strong inter-symbol interference is generated when the amplifier non linear ity is combined with channel memory effects. Further, signals with very high peak to average power ratio, typical of multiple carrier sys tems, are even more sensitive to the non linearities resulting in severe distortion effects. Signal pre-clipping (crest factor reduction) and predistortion are conventional countermeasure techniques to reduce the generated non linear distortion and improve power and spectral efficiency. In this work, novel optimization methods for predistor tion and pre-clipping are analytically derived for a general non-linear communication channel with memory. A combined architecture in which crest factor reduction is followed by signal predistortion is proposed and the parameters are estimated resorting to iterative al gorithms based on least squares method. Performance evaluation of the estimation techniques shows the effectiveness of the derived algorithms and significant gain compared to previously known meth ods.

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“…The main approach is reducing the PAPR, but a peak reduction of the complex baseband signal is generally at the expense of additional distortions. In recent years, some scholars have proposed the technique of combining the crest factor reduction (CFR) and digital predistortion (DPD) [8][9][10][11][12][13][14][15][16][17], which will make considerable improvement in both efficiency and linearity. In [14], a synergetic CFR and DPD design is discussed, which uses a structure similar to the situation in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

A Robust Augmented Combination of Digital Predistortion and Crest Factor Reduction for Rf Power Amplifiers

Zhao¹,

Yu²,

Jian³

et al. 2015

PIER C

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Abstract-This paper proposes a robust combination of digital predistortion (DPD) and crest factor reduction (CFR) for radio frequency (RF) power amplifiers (PAs). It is constructed using the architecture of CFR-DPD connected with a compensation module (CM). The compensation module is introduced to achieve mutual compensation between the output signals of CFR and DPD, and this can reduce the damage to the signal by CFR. The combination of CFR-DPD-CM provides the means to exploit margins in the transmitter performance, allowing the tradeoff among peak-to-average power ratio (PAPR), adjacent channel power ratio (ACPR) and error vector magnitude (EVM). The proposed combination of CFR-DPD-CM is assessed using a GaN Class-F PA driven by two modulated signals (a 4-carrier OFDM signal and a WCDMA 1001 signal with 20-MHz bandwidth), and a GaN Doherty PA driven by a 15-MHz long-term evolution (LTE) signal. The experimental results show that when the CFR reduces the PAPR about 4 dB, applying the proposed combination of CFR-DPD-CM, the average reduction of ACPR is 5.12 dB, and the average reduction of EVM is 1.26% compared with the conventional architecture of CFR-DPD.

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A Combined Approach to Digital Predistortion and Crest Factor Reduction for the Linearization of an RF Power Amplifier

Cited by 35 publications

References 16 publications

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

Generalized direct predistortion with adaptive crest factor reduction control

A Robust Augmented Combination of Digital Predistortion and Crest Factor Reduction for Rf Power Amplifiers

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