A New Companding Technique for PAPR Reduction in OFDM Communication Systems

Gazi, Orhan

doi:10.2316/p.2011.730-061

Cited by 7 publications

(10 citation statements)

References 14 publications

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“…Unfortunately, the model in (25) does not compress the amplitudes of higher power signals, instead it amplifies the amplitude of weak signals only. Based on this, the authors in [27] imposed the logarithmic constraint to achieve high amplitude compression in addition to the expansion of low amplitude signals as follows…”

Section: A Uniformly Distributed Ofdm Signalsmentioning

confidence: 99%

A New Approach to Peak Threshold Estimation for Impulsive Noise Reduction Over Power Line Fading Channels

Adebisi

Anoh

Rabie

et al. 2019

IEEE Systems Journal

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Impulsive noise (IN) is a major component that degrades signal integrity in power line communication (PLC) systems. PLC systems driven by orthogonal frequency-division multiplexing (OFDM) have Rayleigh distributed amplitudes. Based on the dynamic nature of each OFDM symbol, peak amplitude of the symbol was recently shown to be a suitable threshold for detecting IN and this technique outperforms conventional optimal blanking (COB) scheme. In this study, we improve the dynamic peak-based threshold estimation (DPTE) scheme that relies on the OFDM Rayleigh distributed amplitudes by converting the default Rayleigh distribution to uniform distribution to unveil IN with power levels below that of the conventional peak signal. Then, we perform nonlinear mitigation processing on the received signals whose amplitudes exceed the uniformly distributed amplitude using blanking; a scheme we will refer to as uniformly distributed DPTE (U-DPTE). Our results (based on U-DPTE) significantly outperforms DPTE scheme by up to 4dB gain in terms of output signal-to-noise ratio (SNR). Additionally and unlike earlier DPTE studies, we propose a novel threshold criteria that compensates the Gaussian noise power level amplification (after equalization) for achieving optimal SNR over a log-normal multipath fading channel. The results further reveal the sub-optimality of the DPTE scheme over COB.

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Section: A Uniformly Distributed Ofdm Signalsmentioning

confidence: 99%

A New Approach to Peak Threshold Estimation for Impulsive Noise Reduction Over Power Line Fading Channels

Adebisi

Anoh

Rabie

et al. 2019

IEEE Systems Journal

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“…The problem with (8) is that it expands the amplitudes of lower energy signals without compressing the larger ones. Thus, in [14], (8) was modified as…”

Section: Approximation Of Signal Envelope Distributionmentioning

confidence: 99%

“…While the clipping or companding PAPR techniques are performed after OFDM modulation at the transmitter [6], [7], the nonlinear blanking or clipping to mitigate IN are performed at the receiver [11] before OFDM demodulation. Our study is motivated from studying companding transforms which have the ability to significantly reduce PAPR [6], [8], [12]- [14]. Thus, we exploit, in addition to reducing the PAPR, the companding transform for IN mitigation in powerline transmission of OFDM modulated signals.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, we applied the optimization to the search of optimal amplitudes for which the signals can be clipped or blanked to achieve the optimal SNR. The PDFs that characterize these companding transforms are hyperbolic arcsine companding (HASC) [16], exponential companding (EC) [17], µ-law companding (MC) [6], log-based modified MC (LMC) [14] and the error-function companding (ERFC) [13] transforms. We find that among the studied PDFs, the ERFC transform outperforms all others, while the exponential transform is the least performing.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Impulsive Noise Mitigation Scheme for PAPR Reduced OFDM Signals over Powerline Channels

Anoh

Adebisi

Rabie

et al. 2018

2018 IEEE 87th Vehicular Technology Conference (VTC Spring)

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The IEEE 1901 powerline standard can be deployed using orthogonal frequency division multiplexing (OFDM) since it is robust over impulsive channels. However, the powerline channel picks up impulsive interference that the conventional OFDM driver cannot combat. Since the probability density function (PDF) of OFDM amplitudes follow the Rayleigh distribution, it becomes difficult to correctly predict the existence of impulsive noise (IN) in powerline systems. In this study, we use companding transforms to convert the PDF of the conventional OFDM system to a uniform distribution which avails the identification and mitigation of IN. Results show significant improvement in the output signal-to-noise ratio (SNR) when nonlinear optimization search is applied. We also show that the conventional PDF leads to false IN detection which diminishes the output SNR when nonlinear memoryless mitigation scheme such as clipping or blanking is applied. Thus, companding OFDM signals before transmission helps to correctly predict the optimal blanking or clipping threshold which in turn improves the output SNR performance.

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“…Signal distortion methods introduce spectral regrowth or distort the spectrum of the signal and transmit a PAPR signal with no additional information. These techniques comprising clipping and filtering scheme [21][22][23] and compandings methods [2, [24][25][26][27][28][29][30][31][32] which acquire consideration because of its flexibility and simplicity. The idea of companding technique was introduced in [32], which utilizes the μ-law companding technique, which going for lessening PAPR by expanding the average power of the signal while keeping the peak power stays unchanged.…”

Section: Introductionmentioning

confidence: 99%

New Hybrid Schemes for PAPR Reduction in OFDM Systems

Nokaiee¹,

اليمن²,

Alkhawlani³

2018

JST

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The 3rd Generation Partnership Project (3GPP) introduced LTE to meet increasingly demands for communication services with high speed and quality. LTE uses OFDM in the form of OFDMA in the downlink and SCFDMA in the uplink combined with MIMO offering high data rate, high capacity and immunity against multipath channels. However, still the high PAPR of the LTE transmitted signal is the major problem affecting overall system performance degradation and power efficiency. A plenty of research has been devoted to reduce the performance degradation due to the PAPR problem inherent to LTE OFDM systems. A portion of the current techniques such companding methods have low-complexity, no constraint on modulation format and subcarrier size, good distortion and spectral properties; however, they have limited PAPR reduction capabilities. This paper proposes seven new hybrid schemes including Zaddoff Chu Matrix Transform (ZCT) precoding and six modern companding methods; Rooting Companding (RCT), New Error Function Companding (NERF), Absolute Exponential Companding (AEXP), Logarithmic Rooting Companding (LogR), Cosine Companding (COS) and Tangent Rooting Companding (TanhR). Furthermore, the seventh proposed hybrid scheme has been added incorporating ZCT precoding with new proposed companding called Advanced AEXP (AAEXP) companding. The developed methods are combining properties of both ZCT & Compandings, and achieving superior PAPR performance and optimal BER. Simulations results illustrate that the new seven proposed hybrid schemes achieve better PAPR reduction, and BER performance and the best achievement has been achieved by ZCT+AAEXP scheme. Companding Methods( ‫إ�ص��ارة‬ ‫اال‬ ‫�صغ��ط‬ ‫ط��رق‬ ‫وله��ا‬ ،)Subcarrier Size( ‫احلوام��ل‬ ‫ع��دد‬ ‫وحج��م‬ ‫الت�صم��ن‬ ‫�ص��كل‬ ‫عل��ى‬ ‫قي��ود‬ ‫وب��ا‬ ‫التعقي��د،‬ ‫ومنخف�ص��ة‬ ‫البحث‬ ‫هذا‬ ‫اق��رتح‬ ‫وقد‬ ‫�صئيل.‬ ‫مبق��دار‬ PAPR ‫ال�‬ ‫تقلل‬ ‫الط��رق‬ ‫هذه‬ ‫إن‬ ‫فا‬ ‫ذل��ك‬ ‫ومع‬ ‫جي��دة،‬ ‫طيفي��ة‬ ‫خ�صائ��ص‬ ‫م��ع‬ )ZCT(‫ا‬Zaddoff Chu Matrix Transform ‫م��ن‬ ‫مزي��ج‬ ‫أ�صا��ص‬ ‫ا‬ ‫عل��ى‬ ‫جدي��دة‬ ‫هجين��ة‬ ‫ط��رق‬ ‫�صبع��ة‬ New Error‫)،ا‬RCT(‫ا‬Rooting Companding ‫وه��ي‬ ‫إ�ص��ارة‬ ‫اال‬ ‫�صغ��ط‬ ‫ط��رق‬ ‫من‬ ‫خمتلفة‬ ‫أ�صالي��ب‬ ‫ا‬ ‫�ص��ت‬ ‫)،ا‬AEXP(‫ا‬Absolute Exponential Companding‫)،ا‬NERF(‫ا‬Function Companding ،)COS(‫ا‬Cosine Companding‫)،ا‬LogR(‫ا‬Logarithmic Rooting Companding ‫الهجين��ة‬ ‫الطريق��ة‬ ‫تطوي��ر‬ ‫مت‬ ‫ذل��ك‬ ‫إىل‬ ‫ا‬ ‫إ�صاف��ة‬ ‫باال‬ .)TanhR(‫ا‬Tangent Rooting Companding‫و‬ ‫مقرتح��ة‬ ‫جدي��دة‬ ‫طريق��ة‬ ‫م��ع‬ )ZCT(‫ا‬Zaddoff Chu Matrix Transform ‫ال��‬ ‫وجتم��ع‬ ‫ال�صابع��ة‬ ‫خ�صائ��ص‬ ‫ب��ن‬ ‫جتم��ع‬ ‫املتط��ورة‬ ‫الط��رق‬ ‫ه��ذه‬ ‫أن‬ ‫ا‬ ‫النتائ��ج‬ ‫أظه��رت‬ ‫ا‬ .)AAEXP(‫ا‬Advanced AEXP ‫ت�صم��ى‬

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A New Companding Technique for PAPR Reduction in OFDM Communication Systems

Cited by 7 publications

References 14 publications

A New Approach to Peak Threshold Estimation for Impulsive Noise Reduction Over Power Line Fading Channels

A New Approach to Peak Threshold Estimation for Impulsive Noise Reduction Over Power Line Fading Channels

Optimization of Impulsive Noise Mitigation Scheme for PAPR Reduced OFDM Signals over Powerline Channels

New Hybrid Schemes for PAPR Reduction in OFDM Systems

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