The Experts below are selected from a list of 8667 Experts worldwide ranked by ideXlab platform
Antonio Napolitano - One of the best experts on this subject based on the ideXlab platform.
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Oscillatory almost-Cyclostationary signals
Cyclostationary Processes and Time Series, 2020Co-Authors: Antonio NapolitanoAbstract:Abstract Second-order oscillatory almost-Cyclostationary signals have autocorrelation function which is the superposition of amplitude- and angle-modulated complex sinewaves, where the modulating functions, referred to as evolutionary cyclic autocorrelation functions, depend on both time and lag parameter. This class of signals generalizes that of the almost-Cyclostationary signals for which complex sinewaves are not modulated. The problem of statistical function measurements is addressed for the special case of amplitude-modulated time-warped almost-Cyclostationary signals. They constitute a suitable model for the electrocardiogram signal.
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Almost-Cyclostationary signal processing
Cyclostationary Processes and Time Series, 2020Co-Authors: Antonio NapolitanoAbstract:Abstract The processing of almost-Cyclostationary signals is addressed. The linear almost-periodically time-variant filtering is considered and input/output relations are derived in terms of cyclic cross-correlations and cyclic cross-spectra. The cyclic statistics of the signals involved in the Rice's representation are obtained as special cases. The discrete-time signal obtained by uniformly sampling a continuous-time almost-Cyclostationary signal is considered. The cyclic statistical functions of the discrete-time signal are linked to those of the continuous-time signal and aliasing issues are addressed. Multirate processing of discrete-time almost-Cyclostationary signals are also considered.
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EUSIPCO - On characterization and application of oscillatory almost-Cyclostationary processes
2017 25th European Signal Processing Conference (EUSIPCO), 2017Co-Authors: Antonio NapolitanoAbstract:The class of the second-order oscillatory almost-Cyclostationary processes is characterized. These processes have autocorrelation function which is the superposition of amplitude- and angle-modulated complex sinewaves, where the modulating functions, referred to as evolutionary cyclic autocorrelation functions, depend on both time and lag parameter. This class of processes includes that of the almost-Cyclostationary processes. The problem of statistical function measurements is addressed for the special case of amplitude-modulated time-warped almost-Cyclostationary processes. These processes are shown to be a suitable model for the electrocardiogram.
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cyclostationarity limits and generalizations
Signal Processing, 2016Co-Authors: Antonio NapolitanoAbstract:Abstract Recent developments and applications of Cyclostationary signal analysis are reviewed in the companion paper “Cyclostationarity: New trends and applications”. In this paper, limits to the applicability of the Cyclostationary model in the presence of relative motion between transmitter and receiver are enlightened. Two new classes of signals that extend the class of the almost-Cyclostationary signals and allow one to overcome these limits are reviewed. The new classes are those of the generalized almost-Cyclostationary signals and of the spectrally correlated signals. Probabilistic characterization, statistical function estimation, and time-sampling are reviewed for both classes of signals and a comprehensive bibliography commented. The impact of these models on classical problems considered in the Cyclostationary framework is illustrated. Finally, the new class of the oscillatory almost-Cyclostationary processes is introduced and characterized.
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EUSIPCO - Effects of channels introducing time-variant delays on generalized almost-Cyclostationary signals
2002Co-Authors: Luciano Izzo, Antonio NapolitanoAbstract:In this paper, the effects of linear time-variant channels introducing a time-variant delay are studied with reference to the class of the generalized almost-Cyclostationary input signals. Specifically, the Doppler channels existing between a transmitter and a receiver in relative motion is considered in both the cases of constant relative radial speed and constant relative radial acceleration. It is shown that, when excited by an almost Cyclostationary signal, in the first case the channel generates an almost-Cyclostationary output signal whereas in the second case it generates a generalized almost-Cyclostationary output signal.
Huaxia Chen - One of the best experts on this subject based on the ideXlab platform.
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Asymptotically Optimal Likelihood detector for Cyclostationary signature induced by Cyclic Delay Diversity
GLOBECOM - IEEE Global Telecommunications Conference, 2012Co-Authors: Yonglei Jiang, Huaxia Chen, Honglin HuAbstract:The Cyclic Delay Diversity (CDD)-induced Cyclostationary signature is considered to be a robust and cost-efficient scheme for self-coordination of Cognitive Radio Network (CRN). However, the performance of network coordination relies on the reliable detection of such Cyclostationary signatures. In this paper, we deduce an exact covariance matrix to characterize the statistics of Cyclostationary signature. Based on the covariance matrix, we propose an Asymptotically Optimal Likelihood (AOL) detector for the test of the CDD-induced Cyclostationary signature. In addition, an Asymptotically Maximum Likelihood Probability (AMLP) criterion is provided to solve the multiple signatures identification issue. Comprehensive simulations verify that the proposed detector provides superior performance in detection probability and observation duration, compared with the existing Constant False Alarm Rate (CFAR) detector.
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GLOBECOM - Asymptotically Optimal Likelihood detector for Cyclostationary signature induced by Cyclic Delay Diversity
2012 IEEE Global Communications Conference (GLOBECOM), 2012Co-Authors: Yonglei Jiang, Huaxia ChenAbstract:The Cyclic Delay Diversity (CDD)-induced Cyclostationary signature is considered to be a robust and cost-efficient scheme for self-coordination of Cognitive Radio Network (CRN). However, the performance of network coordination relies on the reliable detection of such Cyclostationary signatures. In this paper, we deduce an exact covariance matrix to characterize the statistics of Cyclostationary signature. Based on the covariance matrix, we propose an Asymptotically Optimal Likelihood (AOL) detector for the test of the CDD-induced Cyclostationary signature. In addition, an Asymptotically Maximum Likelihood Probability (AMLP) criterion is provided to solve the multiple signatures identification issue. Comprehensive simulations verify that the proposed detector provides superior performance in detection probability and observation duration, compared with the existing Constant False Alarm Rate (CFAR) detector.
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Sensing of OFDM signals with cyclic delay diversity over doubly-selective fading channels
2011Co-Authors: Jinfeng Tian, Yonglei Jiang, Huaxia ChenAbstract:Orthogonal frequency division multiplexing signals with cyclic delay diversity (CDD) exhibit distinguishable cyclostationarity that can be used to design Cyclostationary signatures for cognitive radio networks. However, such Cyclostationary signatures are
Yang Yang - One of the best experts on this subject based on the ideXlab platform.
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Cyclostationary signatures in ofdm based cognitive radios with cyclic delay diversity
International Conference on Communications, 2009Co-Authors: Haiyou Guo, Yang YangAbstract:The man-induced Cyclostationary signatures can provide a robust mechanism for the self-coordination of cognitive radio networks. However, such artificial signatures incur signaling overhead and come at the bandwidth cost. In this paper, we show intrinsic cyclostaionary signatures in the Orthogonal Frequency Division Multilplexing (OFDM) system with Cyclic Delay Diversity (CDD). The standard conformable CDD technique is initially motivated by the objective for exploiting spatial diversity. Significantly, the underlying periodicity of CDD can simultaneously induce advantageous Cyclostationary signatures without any signaling overhead. The lag-indices of the CDD-induced signatures are uniquely determined by the assigned amount of cyclic delay. Consequently each CDD-OFDM system can be identified by a pre-assigned cyclic delay. The signed system can be easily and robustly recognized through Cyclostationary detection. Furthermore, the CDD-OFDM systems still preserve the cyclic-prefix induced cyclostationarity as primitive OFDM. By exploiting the overall cyclostationarity, we present a desirable cyclostionarity detector with asymptotical constant false alarm rate for spectrum sensing. Comprehensive simulations are also given to show the performance improvement.
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ICC - Cyclostationary Signatures in OFDM-Based Cognitive Radios with Cyclic Delay Diversity
2009 IEEE International Conference on Communications, 2009Co-Authors: Haiyou Guo, Yang YangAbstract:The man-induced Cyclostationary signatures can provide a robust mechanism for the self-coordination of cognitive radio networks. However, such artificial signatures incur signaling overhead and come at the bandwidth cost. In this paper, we show intrinsic cyclostaionary signatures in the Orthogonal Frequency Division Multilplexing (OFDM) system with Cyclic Delay Diversity (CDD). The standard conformable CDD technique is initially motivated by the objective for exploiting spatial diversity. Significantly, the underlying periodicity of CDD can simultaneously induce advantageous Cyclostationary signatures without any signaling overhead. The lag-indices of the CDD-induced signatures are uniquely determined by the assigned amount of cyclic delay. Consequently each CDD-OFDM system can be identified by a pre-assigned cyclic delay. The signed system can be easily and robustly recognized through Cyclostationary detection. Furthermore, the CDD-OFDM systems still preserve the cyclic-prefix induced cyclostationarity as primitive OFDM. By exploiting the overall cyclostationarity, we present a desirable cyclostionarity detector with asymptotical constant false alarm rate for spectrum sensing. Comprehensive simulations are also given to show the performance improvement.
Yonglei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Asymptotically Optimal Likelihood detector for Cyclostationary signature induced by Cyclic Delay Diversity
GLOBECOM - IEEE Global Telecommunications Conference, 2012Co-Authors: Yonglei Jiang, Huaxia Chen, Honglin HuAbstract:The Cyclic Delay Diversity (CDD)-induced Cyclostationary signature is considered to be a robust and cost-efficient scheme for self-coordination of Cognitive Radio Network (CRN). However, the performance of network coordination relies on the reliable detection of such Cyclostationary signatures. In this paper, we deduce an exact covariance matrix to characterize the statistics of Cyclostationary signature. Based on the covariance matrix, we propose an Asymptotically Optimal Likelihood (AOL) detector for the test of the CDD-induced Cyclostationary signature. In addition, an Asymptotically Maximum Likelihood Probability (AMLP) criterion is provided to solve the multiple signatures identification issue. Comprehensive simulations verify that the proposed detector provides superior performance in detection probability and observation duration, compared with the existing Constant False Alarm Rate (CFAR) detector.
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GLOBECOM - Asymptotically Optimal Likelihood detector for Cyclostationary signature induced by Cyclic Delay Diversity
2012 IEEE Global Communications Conference (GLOBECOM), 2012Co-Authors: Yonglei Jiang, Huaxia ChenAbstract:The Cyclic Delay Diversity (CDD)-induced Cyclostationary signature is considered to be a robust and cost-efficient scheme for self-coordination of Cognitive Radio Network (CRN). However, the performance of network coordination relies on the reliable detection of such Cyclostationary signatures. In this paper, we deduce an exact covariance matrix to characterize the statistics of Cyclostationary signature. Based on the covariance matrix, we propose an Asymptotically Optimal Likelihood (AOL) detector for the test of the CDD-induced Cyclostationary signature. In addition, an Asymptotically Maximum Likelihood Probability (AMLP) criterion is provided to solve the multiple signatures identification issue. Comprehensive simulations verify that the proposed detector provides superior performance in detection probability and observation duration, compared with the existing Constant False Alarm Rate (CFAR) detector.
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Sensing of OFDM signals with cyclic delay diversity over doubly-selective fading channels
2011Co-Authors: Jinfeng Tian, Yonglei Jiang, Huaxia ChenAbstract:Orthogonal frequency division multiplexing signals with cyclic delay diversity (CDD) exhibit distinguishable cyclostationarity that can be used to design Cyclostationary signatures for cognitive radio networks. However, such Cyclostationary signatures are
Danijela Cabric - One of the best experts on this subject based on the ideXlab platform.
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Optimizing Wideband Cyclostationary Spectrum Sensing Under Receiver Impairments
IEEE Transactions on Signal Processing, 2013Co-Authors: Eric Rebeiz, Paulo Urriza, Danijela CabricAbstract:In the context of Cognitive Radios (CRs), Cyclostationary detection of primary users (PUs) is regarded as a common method for spectrum sensing. Cyclostationary detectors rely on the knowledge of the signal's symbol rate, carrier frequency, and modulation class in order to detect the present cyclic features. Cyclic frequency and sampling clock offsets are the two receiver impairments considered in this work. Cyclic frequency offsets, which occur due to oscillator frequency offsets, Doppler shifts, or imperfect knowledge of the cyclic frequencies, result in computing the test statistic at an offset from the true cyclic frequency. In this paper, we analyze the effect of cyclic frequency offsets on conventional Cyclostationary detection, and propose a new multi-frame test statistic that reduces the degradation due to cyclic frequency offsets. Due to the multi-frame processing of the proposed statistic, non-coherent integration might occur across frames. Through an optimization framework developed in this work that can be performed offline, we determine the best frame length that maximizes the average detection performance of the proposed Cyclostationary detection method given the statistical distributions of the receiver impairments. As a result of the optimization, the proposed detectors is shown to achieve the performance gains over conventional detectors given the constrained sensing time. We derive the proposed detector's theoretical average detection performance, and compare it to the performance of the conventional Cyclostationary detector. Our analysis shows that gains in average detection performance using the proposed method can be achieved when the effect of sampling clock offset is less severe than that of the cyclic frequency offset. The analysis given in this paper can be used as a design guideline for practical implementation of Cyclostationary spectrum sensors.
