Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

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Access type: Open accessSubject: search.filters.subject.Alpha-stable noise

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Now showing 1 - 6 of 6
  • Conference Object
    Role of Fractional Powers in Manuevering the Fractional Lower-Order Auto-Covariance of Symmetric Alpha-Stable Noise Signals
    (Institute of Electrical and Electronics Engineers Inc., 2019) Ahmed, Areeb; Savacı, Ferit Acar; Wahdan, Muath A.; Othman, Husam
    Since, Fractional Lower-Order Auto-Covariance (FLOAC) remains the only technique to quantify the similarity between alpha-stable (alpha-stable) signals, therefore, the effects of impulsiveness and skewness parameters has also been analyzed before for better generation and detection in various applications. This paper includes the detailed analysis of the FLOAC of symmetric alpha-stable (S alpha S) noise signals in order to observe the possible involvement of the associated fractional powers. The two associated fractional powers of FLOAC has been maneuvered in three possible ways to observe the probable trend of S alpha S noise signals in the presence and absence of Gaussian noise. The observation depicts that the fractional powers largely and solely affect the FLOAC when they are maneuvered collaboratively or even individually where the obtained results can be useful in improving many S alpha S noise signal processing techniques, especially, in the detection of S alpha S noise carrier signals in Random Communication Systems.
  • Conference Object
    Role of Fractional Powers in Maneuvering the Fractional Lower-Order Auto-Covariance of Skewed Alpha-Stable Signals in Gaussian Noise Environment
    (Institute of Electrical and Electronics Engineers Inc., 2019) Ahmed, Areeb; Savacı, Ferit Acar; Wahdan, Muath A.; Othman, Husam
    Since, alpha-stable noise signals similarity can only be gauged by Fractional Lower-Order Auto-Covariance (FLOAC), therefore, the role of impulsiveness and skewness parameters, in generation and detection of the skewed alpha-stable (Sk alpha S) noise signals, has been analyzed several times in the past. However, in this paper, a thorough analysis on the role of fractional powers in changing the FLOAC of Sk alpha S noise signals has been carried out. The two associated fractional powers of FLOAC has been maneuvered in three possible ways to observe the probable trend of Sk alpha S noise signals in the presence and absence of Gaussian noise. According to the observed results, the fractional powers largely and solely affect the FLOAC when they are manipulated collaboratively or even individually where the analyzed results can be handy in enhancing many Sk alpha S noise signal processing techniques, especially, in the detection of Sk alpha S noise carrier signals in Random Communication Systems.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Inverse System Approach To Design Alpha-Stable Noise Driven Random Communication System
    (Institution of Engineering and Technology, 2020) Savacı, Ferit Acar; Ahmed, Areeb
    In the proposed random communication system (RCS), the alpha-stable (alpha-stable) noise as a random carrier drives the transmitter which is modelled by the linear dynamical system and the skewness parameter of the random carrier encodes the binary messages. By selecting the receiver as the inverse system of the transmitter, the output of the receiver is ensured to be alpha-stable noise whose skewness parameters are then estimated to decode the binary messages. The response of a linear system to an alpha-stable process is again alpha-stable process, however, the skewness parameters of the response differs from that of the input which can only be recovered at the output of the inverse system. Hence, estimation of skewness parameter by an eavesdropper, without using the inverse system, will not reveal the true binary messages while the intended receiver truly decodes the binary messages. The proposed inverse system based RCS provides efficient performance which is shown by comparing the bit error rate of the intended receiver and an eavesdropper where the enhancement in covertness is shown by evaluating the covertness values of the proposed RCS.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 8
    Covert Electromagnetic Nanoscale Communication System in the Terahertz Channel
    (World Scientific Publishing, 2020) Ahmed, Areeb; Savacı, Ferit Acar
    In this paper, an electromagnetic nano random communication system (EM-nRCS) has been proposed which ensures covert communication in the terahertz (THz) band. In the proposed system, the skewed alpha-stable noise shift keying method has been used to transmit random noise signals (RNSs) from the nano-transmitter (NT) by utilizing single-walled/carbon nanotubes-based true random number generator (SWCNTs-TRNG) and a graphene-based nano-antenna. A line-of-sight THz transparency window between 0.1 THz and 0.5 THz in the THz channel with spreading loss, molecular absorption loss and molecular absorption noise has been considered. Due to the broadband nature of the RNSs, the proposed EM-nRCS provides efficient transmission by overcoming the high path loss and intense channel noise arising from random fluctuations in the THz band. Non-coherent nano-receiver (NR) consisting of the modified extreme value method (MEVM) estimator has been proposed to extract the hidden binary information in the received RNSs. The bit error rate performance shows that the proposed EM-nRCS ensures high performance and covertness for future EM nanoscale communication devices.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 7
    On Optimizing Fractional Lower Order Covariance Based Synchronization Method for Random Communication Systems
    (Institute of Electrical and Electronics Engineers Inc., 2018) Ahmed, Areeb; Savacı, Ferit Acar
    Previously, the concept of Pilot Assisted Synchronization (PAS) and Fractional Lower Order Covariance (FLOC) has been incorporated together to synchronize alpha-stable noise based communication system which gave birth to Synchronized Random Communication Systems (SRCS). In this paper, an optimization criterion, i.e. FLOC Margin, has been proposed to improve the efficiency of the Fractional Lower Order Covariance based Correlators (FLOCCs) at the receiver side, hence, resulting in enhanced Bit Error Rate (BER) performance of SRCS. Since, the characteristic exponent and impulsiveness parameter are mainly responsible in generating and shaping up the required pilot sequence, therefore, the effects of these parameters on BER performance has also been observed by fluctuating them in their respective ranges. It has been shown that the proposed optimization criterion increases the BER efficiency of SRCS and also reveals the specific range of the characteristic exponent and impulsiveness parameter which can be exploited to achieve the optimum performance.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 15
    Subspace-Based Frequency Estimation of Sinusoidal Signals in Alpha-Stable Noise
    (Elsevier Ltd., 2002) Altınkaya, Mustafa Aziz; Deliç, Hakan; Sankur, Bülent; Anarım, Emin
    In the frequency estimation of sinusoidal signals observed in impulsive noise environments, techniques based on Gaussian noise assumption are unsuccessful. One possible way to find better estimates is to model the noise as an alpha-stable process and to use the fractional lower order statistics (FLOS) of the data to estimate the signal parameters. In this work, we propose a FLOS-based statistical average, the generalized covariation coefficient (GCC). The GCCs of multiple sinusoids for unity moment order in SαS noise attain the same form as the covariance expressions of multiple sinusoids in white Gaussian noise. The subspace-based frequency estimators FLOS-multiple signal classification (MUSIC) and FLOS-Bartlett are applied to the GCC matrix of the data. On the other hand, we show that the multiple sinusoids in SαS noise can also be modeled as a stable autoregressive moving average process approximated by a higher order stable autoregressive (AR) process. Using the GCCs of the data, we obtain FLOS versions of Tufts-Kumaresan (TK) and minimum norm (MN) estimators, which are based on the AR model. The simulation results show that techniques employing lower order statistics are superior to their second-order statistics (SOS)-based counterparts, especially when the noise exhibits a strong impulsive attitude. Among the estimators, FLOS-MUSIC shows a robust performance. It behaves comparably to MUSIC in non-impulsive noise environments, and both in impulsive and non-impulsive high-resolution scenarios. Furthermore, it offers a significant advantage at relatively high levels of impulsive noise contamination for distantly located sinusoidal frequencies.