Influence of input power backoff of nonlinear power amplifier on ber performance of optimal SEFDM signals

Zavjalov, Sergey V.; Fadeev, Dmitrii K.

doi:10.1109/icumt.2016.7765401

Cited by 14 publications

(4 citation statements)

References 17 publications

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“…First, the distortion introduced in the transmit signal by an LS-MIMO transmitter is mainly caused by radio frequency (RF) impairments, such as in-phase/quadrature-phase imbalance, crosstalk, and, predominantly, by high power amplifier (HPA) nonlinearity, especially when HPAs operate close to saturation [14], [17], [18]. Conventionally, applying a large back-off from the saturation power of a PA has been considered as a solution for decreasing the nonlinear distortion since reducing the transmit power allows the PAs to operate in their linear operating region [19]. A serious disadvantage of this solution is that backing off from the saturation level causes PAs to work less energy efficiently, because the PA's ability to generate RF energy decreases when operating away from the saturation point [20].…”

Section: Introductionmentioning

confidence: 99%

On the Energy Efficiency of MIMO Hybrid Beamforming for Millimeter-Wave Systems With Nonlinear Power Amplifiers

Moghadam

Fodor

Bengtsson

et al. 2018

IEEE Trans. Wireless Commun.

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Multiple-input multiple-output (MIMO) millimeter wave (mmWave) systems are vulnerable to hardware impairments due to operating at high frequencies and employing a large number of radiofrequency (RF) hardware components. In particular, nonlinear power amplifiers (PAs) employed at the transmitter distort the signal when operated close to saturation due to energy efficiency considerations. In this paper, we study the performance of a MIMO mmWave hybrid beamforming scheme in the presence of nonlinear PAs. First, we develop a statistical model for the transmitted signal in such systems and show that the spatial direction of the inband distortion is shaped by the beamforming filter. This suggests that even in the large antenna regime, where narrow beams can be steered toward the receiver, the impact of nonlinear PAs should not be ignored. Then, by employing a realistic power consumption model for the PAs, we investigate the trade-off between spectral and energy efficiency in such systems. Our results show that increasing the transmit power level when the number of transmit antennas grows large can be counter-effective in terms of energy efficiency. Furthermore, using numerical simulation, we show that when the transmit power is large, analog beamforming leads to higher spectral and energy efficiency compared to digital and hybrid beamforming schemes.

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Section: Introductionmentioning

confidence: 99%

On the Energy Efficiency of MIMO Hybrid Beamforming for Millimeter-Wave Systems With Nonlinear Power Amplifiers

Moghadam

Fodor

Bengtsson

et al. 2018

IEEE Trans. Wireless Commun.

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“…As far as the research on the nonlinearity of power amplifier is concerned, considerable amount of studies 28–32 focused on the nonlinear effects of field effect transistor (FET) with a total power approaching saturation in order to provide the circuit design and quality improvement with ample solutions of predistortion techniques and equalization algorithms. Firstly proposed by Saleh 33 and widely adopted by many researchers, 34,35 analytical model of nonlinearity in traveling wave tube has benefited qualitative evaluation of its influence on constellation dispersion, bit error rate, and spectrum distribution, whereas regretfully still that those works were regarded as the reference for the structural design optimization to improve the communication quality as well.…”

Section: Introductionmentioning

confidence: 99%

Target recognition for satellite communication by employing higher‐order statistics

Fang

Shi

et al. 2020

Satell Commun Network

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Summary The target recognition for satellite communication (satcom) is generally regarded as the cutting edge of electronic countermeasure research. This work is dedicated to the investigation on the theory and experiment of satellite communication target recognition on the basis of systematical analysis of satcom signal emission, propagation, and reception. The authors elaborate on the fingerprint analysis, feature extraction, and identification of satcom emitters by utilizing the nonlinearities of high‐power microwave vacuum amplifier (HPA). The mechanism of the external subtle features of satcom signal will be also discussed in detail. To acquire the qualified features that precisely represent the individual emitter, higher‐order statistics technique is introduced to implement the feature extraction, and the supervised probabilistic neural network classifier is established to execute the recognition of testing satcom samples. In testing phase, there are a total of 4000 sampling signals with BPSK modulation and variable carrier to noise ratio (CNR) originated by eight types of satcom transmitters setting for the experiment to verify the authors' viewpoints. Thanks to the fine training data set and subsequent well‐extracted features, the PNN classifier had not fail us and finally achieved satisfactory accuracy of more than 94% at CNR level of 10 dB. Those expected results will help to enhance the ability of battlefield surveillance and situational awareness that is of paramount importance in academic research and military application.

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“…A marked contribution of improving spectral efficiency was proposed in 1975 by Mazo [1], where it was proven that, in a single-carrier scenario, a 25% gain in spectral efficiency can be achieved at the same bit error rate (BER) and energy per bit (E b ). In 2003, a multi-carrier system, termed spectrally efficient frequency division multiplexing (SEFDM) [2], [3], which improves spectral efficiency by getting the sub-carriers closer while compromising the orthogonality compared to orthogonal frequency division multiplexing (OFDM) was reported and shown to have advantages in achieving capacity gains [4], [5], choice of signal shapes and power levels [6], [7] and in coexisting with other systems [8]. Other techniques were proposed to improve spectral efficiency by suppressing the out-of-band power level, such as; generalized frequency di-T. Xu, H. Ghannam vision multiplexing (GFDM) [9], filterbank based multicarrier (FBMC) [10] and universal-filtered multi-carrier (UFMC) [11].…”

Section: Introductionmentioning

confidence: 99%

Practical Evaluations of SEFDM: Timing Offset and Multipath Impairments

Xu¹,

Ghannam²,

Darwazeh³

2018

Infocommunications journal

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The non-orthogonal signal waveform spectrally efficient frequency division multiplexing (SEFDM) improves spectral efficiency at the cost of self-created inter carrier interference (ICI). As the orthogonal property, similar to orthogonal frequency division multiplexing (OFDM), no longer exists, the robustness of SEFDM in realistic wireless environments might be weakened. This work aims to evaluate the sensitivity of SEFDM to practical channel distortions using a professional experiment testbed. First, timing offset is studied in a bypass channel to locate the imperfection of the testbed and its impact on SEFDM signals. Then, the joint effect of a multipath frequency selective channel and additive white Gaussian noise (AWGN) is investigated in the testbed. Through practical experiments, we demonstrate the performance of SEFDM in realistic radio frequency (RF) environments and verify two compensation methods for SEFDM. Our results show first frequency-domain compensation works well in frequency non-selective channel conditions while time-domain compensation method is suitable for frequency selective channel conditions. This work paves the way for the application of SEFDM in different channel scenarios.

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Influence of input power backoff of nonlinear power amplifier on ber performance of optimal SEFDM signals

Cited by 14 publications

References 17 publications

On the Energy Efficiency of MIMO Hybrid Beamforming for Millimeter-Wave Systems With Nonlinear Power Amplifiers

On the Energy Efficiency of MIMO Hybrid Beamforming for Millimeter-Wave Systems With Nonlinear Power Amplifiers

Target recognition for satellite communication by employing higher‐order statistics

Practical Evaluations of SEFDM: Timing Offset and Multipath Impairments

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