Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

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

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Institution Author: search.filters.institutionAuthor.Ahmed, AreebSubject: search.filters.subject.Alpha-stable noise

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Structure and Performance Evaluation of Fractional Lower-Order Covariance Method in Alpha-Stable Noise Environments
    (Bentham Science Publishers B.V., 2019) Ahmed, Areeb; Savacı, Ferit Acar
    Background: All existing time delay estimation methods, i.e. correlation and covariance, depend on second or higher-order statistics which are inapplicable for the correlation of alpha-stable noise signals. Therefore, fractional lower order covariance is the most appropriate method to measure the similarity between the alpha-stable noise signals. Methods: In this paper, the effects of skewness and impulsiveness parameters of alpha-stable distributed noise on fractional lower order covariance method have been analyzed. Results: It has been found that auto-correlation, i.e. auto fractional lower order covariance, \ of non delayed alpha-stable noise signals follows a specific trend for specific ranges of impulsiveness and skewness parameters of alpha-stable distributed noise. The results also depict that, by maintaining the skewness and impulsiveness parameters of alpha-stable noise signals in a certain suggested range, better auto-correlation can be obtained between the transmitted and the received alpha-stable noise signals in the absence and presence of additive white Gaussian noise. Conclusion: The obtained results would improve signal processing in alpha-stable noise environment which is used extensively to model impulsive noise in many noise-based systems. Mainly, it would optimize the performance of random noise-based covert communication, i.e. random communication.
  • 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.
  • 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.