Nonlinear effects of power amplification on multicarrier spread spectrum systems

Borich, V.; Jong, Je-Hong; East, J.R.; Stark, W.E.

doi:10.1109/mwsym.1998.689384

Cited by 7 publications

(10 citation statements)

References 2 publications

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“…In (2), is equivalent to AM-AM distortion and to AM-PM distortion. For a narrow-band memoryless system, function can be represented by the odd-order Taylor series as [4]- [7] (3) since the even-order terms are filtered out by the second BPF. The complex coefficients can be obtained from the odd-order complex polynomial fitting of the complex envelope transfer function.…”

Section: Mathematical Model Of An Rf Power Amplifiermentioning

confidence: 99%

“…Most of them build the baseband equivalent mathematical model of a nonlinear power amplifier based on the quadrature decomposition technique that was first proposed by Kaye [1]. The spreading signal is then put into the power amplifier's mathematical model and, by using a fast Fourier transform (FFT) algorithm, the amplified CDMA output spectrum is calculated [2]- [4]. Though this method predicts the output spectrum accurately, it is quite difficult to see how a power amplifier's AM-AM and AM-PM distortions affect the spectral regrowth.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of a CDMA output spectrum based on intermodulation products of two-tone test

Yi¹,

Nam

et al. 2001

IEEE Trans. Microwave Theory Techn.

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Abstract-A prediction method of a code-division multiple-access (CDMA) output spectrum based on intermodulation (IM) products of a two-tone test is proposed in this paper. An RF power amplifier is mathematically modeled by a complex envelope transfer function and, using this model, analytical expressions of IM products and a CDMA output spectrum are derived, respectively. By combining these two expressions, we finally derive an analytical expression that relates IM products to a CDMA output spectrum. It is shown in this expression that not only AM-AM, but also AM-PM distortion affects the CDMA output spectrum. Comparison between the measured and predicted results shows that the output spectrum predicted by this method agrees well with the measured spectrum.Index Terms-AM-AM distortions, AM-PM distortions, CDMA output spectrum, complex envelope transfer function, IM products, RF power amplifier, two-tone test.

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Section: Mathematical Model Of An Rf Power Amplifiermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Prediction of a CDMA output spectrum based on intermodulation products of two-tone test

Yi¹,

Nam

et al. 2001

IEEE Trans. Microwave Theory Techn.

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“…In the last few years, several methods for temporal characterization of power radio frequency (RF) amplifiers have been developed [7], [11]. All of them use an acquisition scheme based on the sampling of the demodulated signal at baseband, as illustrated in the block diagram of Fig.…”

Section: B Acquisition Schemesmentioning

confidence: 99%

“…In this paper, we will use this technique for device characterization and to develop polynomial models with memory from the available data. Several authors have presented polynomial memoryless models [7], tapped-delay-line models [8], Hammerstein models [9], and Volterra models or neural network models [10] using input-output temporal measures in order to identify nonlinear systems.…”

Section: Introductionmentioning

confidence: 99%

Nonlinearity estimation in power amplifiers based on subsampled temporal data

Ibanez-Diaz

Pantaleón

Santamarı́a

et al. 2001

IEEE Trans. Instrum. Meas.

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In this paper we apply subsampling techniques to capture the temporal input-output relationship of RF power amplifiers. This approach avoids the distortion introduced by the upconverter and downconverter stages. We develop polynomial models with memory from the available data and evaluate their performance by estimating device parameters like adjacent channel power ratio (ACPR) and AM-AM curves. The estimated parameters show good agreement with the empirical ones.Index Terms-Adjacent channel power ratio (ACPR), AM-AM curve, nonlinear modeling, power amplifier, subsampling.

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“…Our first claim is that to avoid these drawbacks, the HPA models should be obtained by fitting the input-output time-domain complex envelope of the wideband signal. In the previous years, several methods for time-domain characterization of RF power amplifiers have been proposed [5,6]. In general, these techniques sample a demodulated version of the baseband signal, thus requiring up-and downconverter mixers as well as a preamplifier.…”

Section: Introductionmentioning

confidence: 99%

Modeling Nonlinear Power Amplifiers in OFDM Systems from Subsampled Data: A Comparative Study Using Real Measurements

Santamarı́a

Ibáñez

Lázaro

et al. 2003

EURASIP J. Adv. Signal Process.

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A comparative study among several nonlinear high-power amplifier (HPA) models using real measurements is carried out. The analysis is focused on specific models for wideband OFDM signals, which are known to be very sensitive to nonlinear distortion. Moreover, unlike conventional techniques, which typically use a single-tone test signal and power measurements, in this study the models are fitted using subsampled time-domain data. The in-band and out-of-band (spectral regrowth) performances of the following models are evaluated and compared: Saleh's model, envelope polynomial model (EPM), Volterra model, the multilayer perceptron (MLP) model, and the smoothed piecewise-linear (SPWL) model. The study shows that the SPWL model provides the best in-band characterization of the HPA. On the other hand, the Volterra model provides a good trade-off between model complexity (number of parameters) and performance

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Nonlinear effects of power amplification on multicarrier spread spectrum systems

Cited by 7 publications

References 2 publications

Prediction of a CDMA output spectrum based on intermodulation products of two-tone test

Prediction of a CDMA output spectrum based on intermodulation products of two-tone test

Nonlinearity estimation in power amplifiers based on subsampled temporal data

Modeling Nonlinear Power Amplifiers in OFDM Systems from Subsampled Data: A Comparative Study Using Real Measurements

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