Practical Implementation of Adaptive Analog Nonlinear Filtering for Impulsive Noise Mitigation

IEEE Trans. Veh. Technol.

Nikitin³

et al. 2019

Self Cite

An Adaptive Nonlinear Differential Limiter (ANDL) is proposed in this paper to efficiently alleviate the impact of impulsive noise (IN) in a communication system. Unlike existing nonlinear methods, the ANDL is implemented in the analog domain where the broader acquisition bandwidth makes outliers more detectable and consequently it is easier to remove them. While the proposed ANDL behaves like a linear filter when there is no outlier, it exhibits intermittent nonlinearity in response to IN. Therefore, the structure of the matched filter in the receiver is modified to compensate the filtering effect of the ANDL in the linear regime. In this paper, we quantify the performance of the ANDL by deriving a closed-form analytical bound for the average signal-to-noise ratio (SNR) at the output of the filter. The calculation is based on the idea that the ANDL can be perceived as a time-variant linear filter whose bandwidth is modified based on the intensity of the IN. In addition, by linearizing the filter time parameter variations, we treat the ANDL as a set of linear filters where the exact operating filter at a given time depends upon the magnitude of the outliers. The theoretical average bit error rate (BER) is validated through simulations and the performance gains relative to classical methods such as blanking and clipping are quantified.Index Terms-Impulsive noise (IN), analog nonlinear filter, adaptive nonlinear differential limiter (ANDL), orthogonal frequency-division multiplexing (OFDM).

Section: A Related Workmentioning

confidence: 99%

“…It is worth noting that, we extend the works in [28], [29] by adding matched filter modification module to compensate for the ANDL in the linear regime. The impulse response h mod [k] of the modified matched filter in the discrete domain can be expressed as [30],…”

Section: A Andl Designmentioning

confidence: 99%

Performance Analysis of Analog Intermittently Nonlinear Filter in the Presence of Impulsive Noise

IEEE Trans. Veh. Technol.

Nikitin³

et al. 2019

Self Cite

“…To overcome this drawback, we proposed an Adaptive Nonlinear Differential Limiter (ANDL) to improve the bit-error-rate (BER) performance of uncoded OFDM-based communication systems in an additive noise channel [14], [16]. A practical implementation of Adaptive Canonical Differential Limiter (ACDL) is studied in [15] to compensate for the impulsive noise in OFDM-based powerline communication (PLC) systems.…”

Section: Introductionmentioning

confidence: 99%

Impulsive Noise Mitigation in Underwater Acoustic Communication Systems: Experimental Studies

Sun

2019 IEEE 9th Annual Computing and Communication Workshop and Conference (CCWC)

et al. 2019

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Impulsive noise is a major impediment to orthogonal frequency-division multiplexing (OFDM) based underwater acoustic (UWA) communications. In this work, we evaluate the performance of a memoryless analog nonlinear preprocessor (MANP) that is used to mitigate outliers. The proposed MANP exhibits intermittent nonlinearity only in the presence of the impulsive noise and suppresses the power of outliers based on their amplitudes. Since the outliers are distinguishable in the analog domain prior to anti-aliasing filtering, the MANP outperforms its digital counterparts in all scenarios. Experimental results using data collected in an under-ice environment, demonstrate the superior BER performance of our approach relative to classical nonlinear approaches such as blanking and clipping.Index Terms-Impulsive noise, memoryless analog nonlinear preprocessor (MANP), orthogonal frequency-division multiplexing (OFDM), underwater acoustic (UWA) communications.

“…An iterative joint Doppler shift and IN estimation based on nonlinear least squares (LS) formulation is proposed in [4], which is computationally complex. Bandwidth reduction in the process of analog-to-digital conversion (ADC) is the main drawback of all these digital nonlinear approaches [26], [27]. In [26], an Adaptive Nonlinear Differential Limiter (ANDL) is proposed to improve the bit-error-rate (BER) performance of uncoded OFDM-based powerline communication (PLC) systems in additive noise channel.…”

Section: Introductionmentioning

confidence: 99%

“…In [26], an Adaptive Nonlinear Differential Limiter (ANDL) is proposed to improve the bit-error-rate (BER) performance of uncoded OFDM-based powerline communication (PLC) systems in additive noise channel. A practical implementation of Adaptive Canonical Differential Limiter (ACDL) is studied in [27] to compensate the IN in uncoded OFDM-based PLC systems. The output signal to noise ratio (SNR) and consequently the BER of the linearized ANDL is analytically quantified in [28].…”

Section: Introductionmentioning

confidence: 99%

Intermittently Nonlinear Impulsive Noise Mitigation and Doppler Shift Compensation in UWA-OFDM Systems

Niknam²,

et al. 2019

IEEE Access

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Impulsive noise (IN) and Doppler shift can significantly degrade the performance of orthogonal frequency-division multiplexing (OFDM)-based underwater acoustic (UWA) communication systems. In this paper, we propose a receiver structure that deals efficiently with both these channel impairments in a coded OFDM-based UWA system. First, an analog nonlinear preprocessor (ANP) is proposed to efficiently detect and mitigate IN in an analog domain. The proposed ANP exhibits intermittent nonlinearity when there is impulsivity. Next, the impact of IN on a two-step Doppler shift compensation approach is quantified. Specifically, the ability of the ANP to improve the robustness of Doppler shift compensation in the presence of IN is highlighted. The performance improvement of the proposed receiver is due to the fact that unlike the other nonlinear methods, the ANP is implemented in the analog domain where the outliers are still broadband and distinguishable. The simulation results also demonstrate the superior bit-error-rate (BER) performance of our approach relative to classic approaches that use blanking and/or clipping for IN mitigation. INDEX TERMS Impulsive noise (IN), analog nonlinear preprocessor (ANP), orthogonal frequency-division multiplexing (OFDM), Doppler shift, underwater acoustic (UWA).