A nonlinear adaptive filter for narrowband interference mitigation in spread spectrum systems

Rao, K. Deergha; Swamy, M.N.S.; Plotkin, E.I.

doi:10.1016/j.sigpro.2004.11.005

Cited by 20 publications

(15 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…whereŶ (f ) is the power spectrum of signal y(t),Ψ (f ) is the wavelet notch filter defined in (15), (18), (19) and (22). Thus the filter with m notches has the advantage of being able to adjust notch depth and bandwidth adaptively to filter a large number of jammers in multiple locations by spread-spectrum signal detection.…”

Section: Wavelet Notch Filter Designmentioning

confidence: 99%

“…In order to suppress the narrow-band interference with frequency offset f i by the Gaussian wavelet notch filter designed in (18), (19), (23), consider a notch depth factor c i (0 ≤ c i ≤ 1), and defineŶ…”

Section: System Model and Narrow-band Interference Detectionmentioning

confidence: 99%

“…Narrow-band interference rejection capability of a DSSS system can be enhanced by suitably processing the received signal prior to correlating it with the PN code [25]. Over the past two decades, a significant body of research has been concerned with the development of interference suppression techniques in spread-spectrum systems, such as those processing the signal in the time domain [2,3,11,20] particularly adaptive filtering [5,19] and in the transform/frequency domain [4,16,24] including wavelet transform [14]. Some of these techniques take advantage of the knowledge of the wide spectral shape of the desired signal's spectrum as compared to the interferer's narrow spectrum.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wavelet Notch Filter Design of Spread-Spectrum Communication Systems for High-Precision Wireless Positioning

Luo

2011

Circuits Syst Signal Process

View full text Add to dashboard Cite

Spread-spectrum communication systems are now commonly used in the field of cellular telephone positioning. However, wireless positioning systems by lowpower spread-spectrum communication are extremely vulnerable to high-power interference, which limits achievable measurement precision. In this paper, a bandwidth variable wavelet notch filter design method is proposed to suppress a large number of jammers in multiple locations with noise interfering with spread-spectrum systems. The filter uses combinations of Gaussian wavelets with optimal time-frequency localization and computational efficiency for real-time operation of denoising. The performance of the adaptive filter has been evaluated by experiments associated with a spread-spectrum communication system model employing a reliable noise detector to locate the filter notch. Experimental results demonstrate that the proposed wavelet notch filter removes the narrow-band interference in accordance with the corrupted frequency contents while minimizing signal distortion and information loss, which leads to high-precision wireless positioning.

show abstract

Section: Wavelet Notch Filter Designmentioning

confidence: 99%

Section: System Model and Narrow-band Interference Detectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wavelet Notch Filter Design of Spread-Spectrum Communication Systems for High-Precision Wireless Positioning

Luo

2011

Circuits Syst Signal Process

View full text Add to dashboard Cite

show abstract

“…Adaptive filtering based methods like adaptive notch filters [15][16][17][18], Kalman filter [19], neural network based predictors [19,20], approximate conditional mean (ACM) filter [21,22] and augmented state ACM (ASACM) filter [23,24] are formed based on jamming estimation in frequency domain or time domain. These techniques can be implemented easily in GPS digital signal processors (DSPs) and therefore, they are applicable.…”

Section: Introductionmentioning

confidence: 99%

“…ASACM filter computational complexity increases exponentially in the cases of multi-tone CWI rejection. Also this filter must be combined with a discrete wavelet transform (DWT) filter to overcome jamming attacks with jammer to signal power ratio (JSR) more than 35 dB [19][20][21][22][23][24]. In the notch filters, a zero is placed on a unit circle with a phase equal to the jammer instantaneous frequency (IF) to perfectly remove the jamming [15].…”

Section: Introductionmentioning

confidence: 99%

A New Method for Continuous Wave Interference Mitigation in Single-Frequency GPS Receivers

Mosavi

Moghaddasi

Rezaei

2016

Wireless Pers Commun

View full text Add to dashboard Cite

This paper proposes a new method for jamming suppression in the global positioning system (GPS) receivers. The proposed mitigation technique is based on cascading the adaptive finite impulse response (FIR) filter and the approximate conditional mean (ACM) filter. Adaptive FIR filter puts a notch at the interference frequency, but it causes self-noise in presence of high power jammers. ACM filter is an effective filter for estimating the jamming with known autoregressive process model parameters. However, its performance is degraded in the cases of high power interferences. Cascading these two filters has two advantages: first, collaboration of these two filters can help removing high power jammers. Second, the depth of notch can be limited by a threshold in presence of high power jammers to prevent self-noise effect. In such a case, the ACM filter can help to remove the remaining jamming effects on GPS signal. The performance of proposed method is analyzed in presence of single and multiple continuous wave interferences. Experimental results show the benefits of proposed method on terms of signal to noise power ratio improvement and mean square error compared to previous methods.

show abstract

On‐line wavelet filtering of narrowband noise in signal detection of spread spectrum system for location tracking

Luo¹

2011

Int J Communication

View full text Add to dashboard Cite

SUMMARY Spread spectrum signal transmitted by wireless channel for location tracking can be severely corrupted by noise due to external disturbances. Narrowband noise is the most effective interference that can make measurement signal undetected. However, the current methods for narrowband interference (NBI) suppression are either very time‐consuming or add distortion to the signal received. In this paper, an adaptive Gaussian wavelet filter with optimal time–frequency localization and variable notch depth is proposed to suppress a large number of NBIs with additive white Gaussian noise and pulsed noise that interfere with the spread spectrum communication system. The filtering of both continuous and time‐varying NBIs with fast resampling is performed in conjunction with the fast Fourier transform‐based correlation for peak detection, and is computationally efficient for real‐time operation of signal detection. The performance of the adaptive filter has been evaluated by experiments employing a reliable noise detector. Experimental results demonstrate that the proposed wavelet filter isolates the signals from the NBI in accordance with the corrupted frequency contents while preserving the desired spread spectrum signal, and improves signal to noise ratio for peak detection leading to higher accuracy of timing measurement for real‐time wireless location. Copyright © 2011 John Wiley & Sons, Ltd.

show abstract

A nonlinear adaptive filter for narrowband interference mitigation in spread spectrum systems

Cited by 20 publications

References 10 publications

Wavelet Notch Filter Design of Spread-Spectrum Communication Systems for High-Precision Wireless Positioning

Wavelet Notch Filter Design of Spread-Spectrum Communication Systems for High-Precision Wireless Positioning

A New Method for Continuous Wave Interference Mitigation in Single-Frequency GPS Receivers

On‐line wavelet filtering of narrowband noise in signal detection of spread spectrum system for location tracking

Contact Info

Product

Resources

About