Loading...
Search for: block-sparse-signal
0.006 seconds

    Spectrum Sensing in Cognitive Radios Using Compressive Sensing and Random Sampling

    , M.Sc. Thesis Sharif University of Technology Dezfouli, Milad (Author) ; Marvasti, Farrokh (Supervisor)
    Abstract
    Cognitive radio (CR) can successfully deal with the growing demand and scarcity of the wireless spectrum. To exploit limited spectrum efficiently, CR technology allows unlicensed users to access licensed spectrum bands. Since licensed users have priorities to use the bands, the unlicensed users need to continuously monitor the licensed users activities to avoid interference and collisions. How to obtain reliable results of the licensed users activities is the main task for spectrum sensing. Based on the sensing results, the unlicensed users should adapt their transmit powers and access strategies to protect the licensed communications. The requirement naturally presents challenges to the... 

    Energy allocation for parameter estimation in block CS-based distributed MIMO systems

    , Article 2015 International Conference on Sampling Theory and Applications, SampTA 2015, 25 May 2015 through 29 May 2015 ; May , 2015 , Pages 523-527 ; 9781467373531 (ISBN) Abtahi, A ; Modarres Hashemi, M ; Marvasti, F ; Tabataba, F. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    Exploiting Compressive Sensing (CS) in MIMO radars, we can remove the need of the high rate A/D converters and send much less samples to the fusion center. In distributed MIMO radars, the received signal can be modeled as a block sparse signal in a basis. Thus, block CS methods can be used instead of classical CS ones to achieve more accurate target parameter estimation. In this paper a new method of energy allocation to the transmitters is proposed to improve the performance of the block CS-based distributed MIMO radars. This method is based on the minimization of an upper bound of the sensing matrix block-coherence. Simulation results show a significant increase in the accuracy of multiple... 

    Distribution-aware block-sparse recovery via convex optimization

    , Article IEEE Signal Processing Letters ; Volume 26, Issue 4 , 2019 , Pages 528-532 ; 10709908 (ISSN) Daei, S ; Haddadi, F ; Amini, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    We study the problem of reconstructing a block-sparse signal from compressively sampled measurements. In certain applications, in addition to the inherent block-sparse structure of the signal, some prior information about the block support, i.e., blocks containing non-zero elements, might be available. Although many block-sparse recovery algorithms have been investigated in the Bayesian framework, it is still unclear how to incorporate the information about the probability of occurrence into regularization-based block-sparse recovery in an optimal sense. In this letter, we bridge between these fields by the aid of a new concept in conic integral geometry. Specifically, we solve a weighted... 

    EEG Source Localization Using Block Sparse Structure in Reduced Dimension Leadfield

    , M.Sc. Thesis Sharif University of Technology Khanzamani Mohammadi, Ali (Author) ; Babaiezadeh, Massoud (Supervisor) ; Ghazizadeh, Ali (Co-Supervisor)
    Abstract
    Electroencephalogram (EEG) brain source localization carries many potential applications in systems and cognitive neuroscience, and for treatment of various neurological problems such as epilepsy. According to some recent studies, determining the spatial extent of sources and estimating their true time courses have proved challenging. This master's thesis proposes a method for localizing extended brain sources. Cortical surface parcellation has been used to reduce the dimension of the inverse problem without losing much information. The active regions are assumed to be sparse and the time course of the sources exhibits a correlation structure. The reduced dimension problem was then solved by... 

    Outlier Censoring Based on Sparse Signal Recovery Algorithms

    , M.Sc. Thesis Sharif University of Technology Bassak, Elaheh (Author) ; Karbasi, Mohammad (Supervisor)
    Abstract
    In today’s world, knowledge of the statistical behavior of noise can tremendously affect the accuracy of target detection in radar systems. Therefore, radar systems commonly collect a secondary dataset of homogeneous noise and estimate the statistics of the gathered data, prior to attempting target detection. Specifically, in the case of Gaussian noise with a mean of zero, the entire statistical information of the noise is encoded in its covariance matrix. In practice, however, the challenge is that the training samples do not purely contain homogeneous noise. In fact, some samples contain non-homogeneous outlier signals that do not have the same distribution as the noise samples. In this...