Vyacheslav Tuzlukov

Kyungpook National University, Daikyū, Daegu, South Korea

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Publications (52)9.87 Total impact

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    Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: The most commonly used spectrum sensing techniques in cognitive radio (CR) networks, such as the energy detector (ED), matched filter (MF), and others, suffer from the noise uncertainty and signal-to-noise ratio (SNR) wall phenomenon. These detectors cannot achieve the required signal detection performance regardless of the sensing time. In this paper, we explore a signal processing scheme, namely, the generalized detector (GD) constructed based on the generalized approach to signal processing (GASP) in noise, in spectrum sensing of CR network based on antenna array with the purpose to alleviate the SNR wall problem and improve the signal detection robustness under the low SNR. The simulation results confirm our theoretical issues and effectiveness of GD implementation in CR networks based on antenna array.
    Preview · Article · Jul 2015 · Sensors
  • M. S. Shbat · V. P. Tuzlukov
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    ABSTRACT: The implementation of the generalized detector (GD) in cognitive radio (CR) systems allows us to improve the spectrum sensing performance in comparison with employment of the conventional detectors. We analyze the spectrum sensing performance for the uncorrelated and spatially correlated receive antenna array elements. Additionally, we consider a practical case when the noise power at the output of GD linear systems (the preliminary and additional filters) is differed by value. The choice of the optimal GD threshold based on the minimum total error rate criterion is also discussed. Simulation results demonstrate superiority of GD implementation in CR system as spectrum sensor in comparison with the energy detector (ED), weighted ED (WED), maximum-minimum eigenvalue (MME) detector, and generalized likelihood ratio test (GLRT) detector.
    No preview · Article · Jun 2015 · Radioengineering
  • Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: An adaptive detection threshold under employment of the generalised detector (GD) in radar sensor systems is defined. GD is constructed in accordance with the generalised approach to signal processing in noise. To define the GD adaptive threshold based on the observed noise samples, the authors apply an appropriate noise power estimation technique. This study deals with an adaptive GD detection threshold definition as a function of the estimated noise power. Under investigations, they use two noise power estimation procedures. The first is the sliding window technique with the reference cells. The second procedure is based on the adaptive noise power estimation. Comparative analysis of simulation results demonstrates superiority by detection performance in favour of GD implementation in comparison with the well-known constant false alarm rate (CFAR) detectors, namely, cell averaging CFAR and ordered statistics CFAR detectors.
    No preview · Article · Aug 2014 · IET Signal Processing
  • M. Shbat · V. Tuzlukov
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    ABSTRACT: The detection performance of the generalized detector (GD) constructed based on the generalized approach to signal processing in noise is evaluated under homogeneous and non-homogeneous noise. The GD adaptive threshold is derived and defined applying an appropriate noise power estimation using the sliding window technique. The direct close expressions for the GD average probability of detection and probability of false alarm are also derived. Typical constant false alarm rate (CFAR) detectors, namely, the cell averaging CFAR (CA-CFAR) detector, the ordered statistic CFAR (OS-CFAR) detector, the generalized censored mean level (GCML) detector, and the adaptive censored greatest-of CFAR (ACGO-CFAR) detector are compared with the GD by detection performance under both homogeneous and non-homogeneous noise conditions, i.e. when the interfering targets are absent or present, respectively. Simulation results demonstrate a superiority of GD in detection performance in comparison with the above mentioned CFAR detectors under both homogeneous and non-homogeneous noise conditions.
    No preview · Article · Apr 2014 · Radioengineering
  • V. Tuzlukov
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    ABSTRACT: In this paper, we address an adaptive detection of range-spread targets or targets embedded in Gaussian noise with unknown covariance matrix by the generalized detector (GD) based on the generalized approach to signal processing (GASP) in noise. We assume that cells or secondary data that are free of signal components are available. Those secondary data are supposed to process either the same covariance matrix or the same structure of the covariance matrix of the cells under test. In this context, under designing GD we use a twostep procedure. The criteria lead to receivers ensuring the constant false alarm rate (CFAR) property with respect to unknown quantities. A thorough performance assessment of the proposed detection strategies highlights that the two-step design procedure of decision-making rule in accordance with GASP is to be preferred with respect to the plain one. In fact, the proposed design procedure leads to GD that achieves significant improvement in detection performance under several situation of practical interest. For estimation purposes, we resort to a set of secondary data. In addition to the classical homogeneous scenario, we consider the case wherein the power value of primary and secondary data vectors is not the same. The design of adaptive detection algorithms based on GASP in the case of mismatch is a problem of primary concern for radar applications. We demonstrate that two-step design procedure based on GASP ensures minimal loss.
    No preview · Article · Jan 2014 · WSEAS Transactions on Communications
  • V. Tuzlukov
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    ABSTRACT: Probability of bit-error Per performance of asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless communication systems employing the generalized detector (GD) constructed based on the generalized approach to signal processing in noise is analyzed. The effects of pulse shaping, quadriphase or direct sequence quadriphase shift keying (DS-QPSK) spreading, aperiodic spreading sequences are considered in DS-CDMA based on GD and compared with the coherent Neyman-Pearson receiver. An exact probability of error Per expression and several approximations, namely, one using the characteristic function method, a simplified expression for the improved Gaussian approximation (IGA) and the simplified improved Gaussian approximation are derived. Under conditions typically satisfied in practice and even with a small number of interfe-rers, the standard Gaussian approximation (SGA) for the multiple-access interference component of the GD test statistic and the probability of error Per performance is shown to be accurate. Moreover, the IGA is shown to reduce to the SGA for pulses with zero excess bandwidth. Second, the GD probability of error Per performance of quadriphase DS-CDMA is shown to be superior to that of bi-phase DS-CDMA. Numerical examples by Monte Carlo simulation are presented to illustrate the GD probability of error Per performance for square-root raised-cosine pulses and spreading factors of moderate to large values. Superiority of GD employment in CDMA sysems over the Neyman-Pearson receiver is demonstrated.
    No preview · Article · Jan 2014 · WSEAS Transactions on Communications
  • M.S. Shbat · V. Tuzlukov
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    ABSTRACT: This chapter is devoted to a target return signal detection performance evaluation of detectors employed by radar sensor systems used in vehicle safety systems, for example, safety driving applications. Detection performance and characteristics of several types of the constant false alarm rate (CFAR) detectors and the generalized detector (GD) constructed based on the generalized approach to signal proceeding in noise are compared under the same conditions for the cases of presence and absence of interfering vehicles. The method of definition of the required target vehicle parameters for the middle range radar (MRR) and short range radar (SRR) applications is also discussed.
    No preview · Chapter · Jan 2014
  • J. Liu · V. Tuzlukov
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    ABSTRACT: We investigate the generalized receiver (GR) constructed based on the generalized approach to signal processing in noise employing non-blind beamforming algorithms and direction of arrival (DOA) estimation, which is implemented by multiple-input multiple-output (MIMO) wireless communication systems. We compare three non-blind beamforming algorithms, namely, the least mean square (LMS), the recursive least square (RLS), and the sample matrix inverse (SMI) algorithms under GR employment in MIMO wireless communication systems. DOA estimation techniques are applied based on multiple signal classification (MUSIC) and estimation of signal parameters via rotational invariance technique (ESPRIT). We suppose several GR structures employing the above mentioned non-blind beamforming algorithms jointly with DOA estimation procedure. Comparative analysis of simulation results allows us to conclude that the performance curves of GR with considered non-blind beamforming algorithms are very close to each other. Also, simulation results demonstrate superiority in the output signal-to-interference-plus-noise ratio (SINR) under employment of GR with the discussed non-blind beamforming algorithms and DOA estimation in MIMO wireless communication systems in comparison with the correlation receiver that is optimal in the Neyman-Pearson sense if a priori information about the information signal parameters is known.
    No preview · Article · Jan 2014 · WSEAS Transactions on Communications
  • V. Tuzlukov
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    ABSTRACT: In this paper, we consider the problem of M-ary signal detection based on the generalized approach to signal processing (GASP) in noise over a single-input multiple-output (SIMO) channel affected by the frequency-dispersive Rayleigh distributed fading and corrupted by the additive non-Gaussian noise modelled as spherically invariant random process. We derive both the optimum generalized detector (GD) structure based on GASP and a suboptimal reduced-complexity GD applying the low energy coherence approach jointly with the GASP in noise. Both GD structures are independent of the actual noise statistics. We also carry out a performance analysis of both GDs and compare with the conventional receivers. The performance analysis is carried out with reference to the case that the channel is affected by a frequency-selective fading and for a binary frequency-shift keying (BFSK) signalling format. The results obtained through both a Chernoff-bounding technique and Monte Carlo simulations reveal that the adoption of diversity also represents a suitable means to restore performance in the presence of dispersive fading and impulsive non-Gaussian noise. It is also shown that the suboptimal GD incurs a limited loss with respect to the optimum GD and this loss is less in comparison with the conventional receiver.
    No preview · Article · Jan 2014 · WSEAS Transactions on Signal Processing
  • Source
    Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: We derive the probability of false alarm and detection threshold under employment of the generalized detector (GD) in cognitive radio (CR) systems for two scenarios: firstly, the independent antenna array elements; the secondly, the correlated antenna array elements. The energy detector (ED) and GD spectrum sensing performances are compared under the same initial conditions. The simulation results show that implementation of the GD improves the spectrum sensing performance in CR systems both for independent and correlated antenna array elements.
    Preview · Article · Jun 2013 · International Journal of Antennas and Propagation
  • Source
    Daina Das · Hritom Das · Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: The bit error rate (BER) performance of wireless communication system employing the generalized receiver (GR) under the binary phase shift keying (BPSK) modulation over Rayleigh fading channel with three common diversity combining techniques, namely, the selection combining, equal gain combining, and maximal ratio combining with the purpose to mitigate the effects of multipath fading is investigated. Simulation demonstrates a high performance gain under employment of GR in wireless communication system in comparison with modern approaches.
    Full-text · Article · May 2013
  • J. Liu · M.S. Shbat · V. Tuzlukov
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    ABSTRACT: Under implementation of the generalized receiver (GR) constructed based on the generalized approach to signal processing (GASP) in noise there is a need to cancel an interference to improve the GR performance. In this paper, we discuss an interference cancellation technique based on the non-blind beamfroming algorithm, namely, the least mean square (LMS) algorithm employed by GR. The direction of arrival (DOA) estimation is also used by LMS algorithm to provide a priori knowledge about the desired signal in GR. The simulation results demonstrate a superiority of GR performance in comparison with the Neyman-Pearson (NP) receiver.
    No preview · Article · Jan 2013
  • D. Das · M.S. Shbat · V. Tuzlukov
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    ABSTRACT: The bit error rate (BER) performance analysis of transmit beamforming technique employing the generalized receiver (GR) under the binary phase shift keying (BPSK) modulation over Rayleigh fading channel is investigated. The scheme uses two transmit antennas and one receive antenna. Simulation result demonstrates a high performance gain under employment of GR with transmit beamforming technique in comparison with the neyman pearson (NP) receiver under the same conditions.
    No preview · Conference Paper · Jan 2013
  • Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: A great problem for LTE networks employed large number of femtocells using the self optimization and configuration capabilities is to reduce the operational efforts. The handover process is a key element that has to be considered to improve efficiently the performance of the adopted femtocell technology and LTE network. This paper is devoted to a femtocell-to-femtocell handover approach based on simple feedback technique and existence of interface working as signalling system (SS). This interface allows us to exchange the priority lists and other signalling messages between femtocells, and helps us to overcome the drawbacks to use the public internet serving as control messages paths to handle the handover process.
    No preview · Conference Paper · Oct 2012
  • Jin Gui Liu · Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: This paper deals with applying the adaptive non-blind beamforming (NB-BF) based on the least mean square (LMS) algorithm employed by the generalized receiver (GR) that is constructed according to the generalized approach to signal processing (GASP) in noise. The simulation results show good ability to cancel the interference at the GR output using the proposed combination.
    No preview · Conference Paper · Oct 2012
  • Modar Safir Shbat · Vyacheslav Tuzlukov
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    ABSTRACT: Radar sensors are an attractive technology for different kinds of applications, especially, in the case of safety driving systems. This research deals with designing the target return signal detection algorithm for radar sensors using the generalized detector (GD) with adaptive detection threshold based on a sliding window technique to estimate the noise power. The general GD structure is introduced, and the proposed method to define the adaptive detection threshold is assumed to be employed by 24 GHz frequency modulation continuous wave (FMCW) radar sensor and the simulation results show the better detection performance in comparison with the cell averaging constant false alarm rate (CA-CFAR) detector one which is widely used by radar sensor systems for car applications.
    No preview · Conference Paper · May 2012
  • Vyacheslav Tuzlukov
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    ABSTRACT: The parametric Rao test for multichannel adaptive signal detection by the adaptive generalized detector (GD) constructed based on the generalized approach to signal processing in noise is derived by modeling the disturbance signal as a multichannel autoregressive process. The parametric Rao test takes a form identical to that of parametric GD for space-time adaptive processing in airborne surveillance radar systems and other similar applications. The equivalence offers new insights into the performance and implementation of the GD. Specifically, the Rao/GD is asymptotically (in the case of large samples) a parametric generalized likelihood ratio test generalized detector (GLRT GD) due to an asymptotic equivalentce between the Rao test and the GLRT/GD. The asymptotic distribution of the Rao/GD test statistic is obtained in closed form, which follows an exponential distribution under the null hypothesis (the target return signal is absent) and, respectively, a non-central Chi-squared distribution with two degrees of freedom under the alternative hypothesis (the target return signal is present). The noncentrality parameter of the noncentral Chi-squared distribution is determined by the output signal-to-interference-plus-noise ratio of a temporal whitening filter. Since the asymptotic distribution under the null hypothesis is independent of the unknown parameters, the Rao/GD asymptotically achieves constant false alarm rate (CFAR) GD. Numerical results show that these results are superior in predicting the performance of the parametric adaptive matched filter detector even with moderate data support.
    No preview · Article · May 2012 · Proceedings of SPIE - The International Society for Optical Engineering
  • Vyacheslav Tuzlukov
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    ABSTRACT: Probability of bit-error Per performance of asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless communication systems employing the generalized detector (GD) constructed based on the generalized approach to signal processing in noise is analyzed. The effects of pulse shaping, quadriphase or direct sequence quadriphase shift keying (DS-QPSK) spreading, aperiodic spreading sequences are considered in DS-CDMA based on GD and compared with the coherent Neyman-Pearson receiver. An exact Per expression and several approximations: one using the characterristic function method, a simplified expression for the improved Gaussian approximation (IGA) and the simplified improved Gaussian approximation are derived. Under conditions typically satisfied in practice and even with a small number of interferers, the standard Gaussian approximation (SGA) for the multiple-access interference component of the GD statistic and Per performance is shown to be accurate. Moreover, the IGA is shown to reduce to the SGA for pulses with zero excess bandwidth. Second, the GD Per performance of quadriphase DS-CDMA is shown to be superior to that of bi-phase DS-CDMA. Numerical examples by Monte Carlo simulation are presented to illustrate the GD Per performance for square-root raised-cosine pulses and spreading factors of moderate to large values. Also, a superiority of GD employment in CDMA systems over the Neyman-Pearson receiver is demonstrated
    No preview · Article · May 2012 · Proceedings of SPIE - The International Society for Optical Engineering
  • Vyacheslav Tuzlukov
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    ABSTRACT: We consider a problem of detecting a random spatially distributed signal source by an array of sensors based on the generalized approach to signal processing in noise. We derive some generalized detector (GD) structures under several assumptions on the available statistics. The GD performance is evaluated and the effect of source angular spread is investigated. We notice the degrees of freedom of detection statistic distributions depend on both the signal angular spread and the number of data snapshots. At high signal-to-noise ratio and with small degrees of freedom, an increase of angular spread improves the detection performance. With large degrees of freedom the increase of angular spread reduces the detection performance. A comparison between GD and conventional beamformer is carried out by computer simulations. The results indicate a superiority of GD as the angular spread becomes large over the conventional beamformer detector.
    No preview · Article · May 2012 · Proceedings of SPIE - The International Society for Optical Engineering
  • Source
    Vyacheslav Tuzlukov

    Preview · Chapter · Mar 2012

Publication Stats

64 Citations
9.87 Total Impact Points

Institutions

  • 2009-2015
    • Kyungpook National University
      • • College of IT Engineering
      • • Department of Electrical Engineering
      • • School of Computer Science and Engineering
      Daikyū, Daegu, South Korea
  • 2008
    • Yeungnam University
      • Department of Electronic Engineering
      Asan, South Chungcheong, South Korea
  • 2004-2005
    • Ajou University
      • Department of Electrical and Computer Engineering
      Sŏul, Seoul, South Korea