Browsing by Subject "Impulsive noise"

Now showing 1 - 4 of 4

Open Access
Dürtün gürültüye karşı sağlam küme üyeliği süzgeç algoritmaları
(IEEE, 2014-04) Sayın, Muhammed Ö.; Vanlı, N. Denizcan; Kozat, Süleyman S.
Bu bildiride, dürtün gürültüye karşı sağlam küme üyeliği süzgeç algoritmaları öneriyoruz. İlk olarak küme üyeliği düzgelenmiş en küçük mutlak fark algoritmasını (SM-NLAD) tanıtıyoruz. Bu algoritma hatanın karesi yerine mutlak değerini maliyetlendirerek dürtün gürültüye karşı sağlamlık sağlar. Sonra bu algoritmanın dürtün gürültünün olmadığı ortamlarda da diğer algoritmalarla karşılaştırılabilir performans sergilemesi için logaritmik maliyet çerçevesinden yararlanarak küme üyeliği düzgelenmiş en küçük logaritmik mutlak fark algoritmasını (SMNLLAD) öneriyoruz. Logaritmik maliyet fonksiyonu doğal olarak büyük hata değerlerinin mutlak değerini içerirken küçük hata değerlerinin karesini içerir. Son olarak, sayısal deneylerimizde algoritmalarımızın dürtün gürültülere karşı sağlamlığını ve dürtün gürültünün olmadığı ortamlarda da karşılaştırılabilir performans sergilediğini gösteriyoruz.
Open Access
Robust adaptive algorithms for underwater acoustic channel estimation and their performance analysis
(2017-09) Marivani, Iman
We introduce a novel family of adaptive robust channel estimators for highly chal- lenging underwater acoustic (UWA) channels. Since the underwater environment is highly non-stationary and subjected to impulsive noise, we use adaptive ltering techniques based on minimization of a logarithmic cost function, which results in a better trade-off between the convergence rate and the steady state performance of the algorithm. To improve the convergence performance of the conventional rst and second order linear estimation methods while mitigating the stability issues related to impulsive noise, we intrinsically combine different norms of the error in the cost function using a logarithmic term. Hence, we achieve a com- parable convergence rate to the faster algorithms, while signi cantly enhancing the stability against impulsive noise in such an adverse communication medium. Furthermore, we provide a thorough analysis for the tracking and steady-state performances of our proposed methods in the presence of impulsive noise. In our analysis, we not only consider the impulsive noise, but also take into account the frequency and phase offsets commonly experienced in real life experiments. We demonstrate the performance of our algorithms through highly realistic experi- ments performed on accurately simulated underwater acoustic channels.
Open Access
Robust adaptive algorithms for underwater acoustic channel estimation and their performance analysis
(Elsevier Inc., 2017) Kari, D.; Marivani, I.; Khan, F.; Sayin, M. O.; Kozat, S. S.
We introduce a novel family of adaptive robust channel estimators for highly challenging underwater acoustic (UWA) channels. Since the underwater environment is highly non-stationary and subjected to impulsive noise, we use adaptive filtering techniques based on minimization of a logarithmic cost function, which results in a better trade-off between the convergence rate and the steady state performance of the algorithm. To improve the convergence performance of the conventional first and second order linear estimation methods while mitigating the stability issues related to impulsive noise, we intrinsically combine different norms of the error in the cost function using a logarithmic term. Hence, we achieve a comparable convergence rate to the faster algorithms, while significantly enhancing the stability against impulsive noise in such an adverse communication medium. Furthermore, we provide a thorough analysis for the tracking and steady-state performances of our proposed methods in the presence of impulsive noise. In our analysis, we not only consider the impulsive noise, but also take into account the frequency and phase offsets commonly experienced in real life experiments. We demonstrate the performance of our algorithms through highly realistic experiments performed on accurately simulated underwater acoustic channels.
Open Access
Robust direction-of-arrival estimation in non-Gaussian noise
(Institute of Electrical and Electronics Engineers, 1998-05) Yardımcı, Y.; Çetin, A. Enis; Cadzow, J. A.
In this correspondence, a nonlinearly weighted least-squares method is developed for robust modeling of sensor array data. Weighting functions for various observation noise scenarios are determined using maximum likelihood estimation theory. Computational complexity of the new method is comparable with the standard least-squares estimation procedures. Simulation examples of direction-of-arrival estimation are presented.