Conference Paper

Multiantenna spectrum sensing: Detection of spatial correlation among time-series with unknown spectra.

Commun. Eng. Dept., Univ. of Cantabria, Santander, Spain
DOI: 10.1109/ICASSP.2010.5496151 Conference: Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2010, 14-19 March 2010, Sheraton Dallas Hotel, Dallas, Texas, USA
Source: DBLP

ABSTRACT One of the key problems in cognitive radio (CR) is the detection of primary activity in order to determine which parts of the spectrum are available for opportunistic access. This detection task is challenging, since the wireless environment often results in very low SNR conditions. Moreover, calibration errors and imperfect analog components at the CR spectral monitor result in uncertainties in the noise spectrum, making the problem more difficult. In this work, we present a new multiantenna detector which is based on the fact that the observation noise processes are spatially uncorrelated, whereas any primary signal present should result in spatial correlation. In particular, we derive the generalized likelihood ratio test (GLRT) for this problem, which is given by the quotient between the determinant of the sample covariance matrix and the determinant of its block-diagonal version. For stationary processes the GLRT tends asymptotically to the integral of the logarithm of the Hadamard ratio of the estimated power spectral density matrix. Additionally, we present an approximation of the frequency domain detector in the low SNR regime, which results in computational savings. The performance of the proposed detectors is evaluated by means of numerical simulations, showing important advantages over existing detectors.

0 Bookmarks
 · 
48 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Spectrum sensing is a key component of the cognitive radio paradigm. Primary signals are typically detected with uncalibrated receivers at signal-to-noise ratios (SNRs) well below decodability levels. Multiantenna detectors exploit spatial independence of receiver thermal noise to boost detection performance and robustness. We study the problem of detecting a Gaussian signal with rank- P unknown spatial covariance matrix in spatially uncorrelated Gaussian noise with unknown covariance using multiple antennas. The generalized likelihood ratio test (GLRT) is derived for two scenarios. In the first one, the noises at all antennas are assumed to have the same (unknown) variance, whereas in the second, a generic diagonal noise covariance matrix is allowed in order to accommodate calibration uncertainties in the different antenna frontends. In the latter case, the GLRT statistic must be obtained numerically, for which an efficient method is presented. Furthermore, for asymptotically low SNR, it is shown that the GLRT does admit a closed form, and the resulting detector performs well in practice. Extensions are presented in order to account for unknown temporal correlation in both signal and noise, as well as frequency-selective channels.
    IEEE Transactions on Signal Processing 09/2011; · 2.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we propose a robust energy detector for spectrum sensing in cognitive radio systems. The detector is derived by modelling the noise process as consisting of two components, Gaussian noise and impulsive noise. The impulsive noise is modelled using a uniform distribution that appears with a certain probability. A convenient approximation using the max operator is then applied to the resulting probability density function to gain mathematical tractability. The performance of the proposed detector is analysed theoretically and the results of the theoretical analysis are verified in our simulation study.
    IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2011, Toronto, ON, Canada, September 11-14, 2011; 01/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Running a Network Management Protocol is imperative to ensure network connectivity and stability especially in highly dynamic environment of future Cognitive Radio Sensor Networks. Such protocols have to be characterized by their light overhead in terms of energy, communication and implementation. A solution in this respect is hereby proposed to enable a node in a multichannel environment to quickly establish a control channel with neighboring nodes. The channel selection scheme leverages on the strength of both Dedicated Control Channel and Hopping schemes by implementing a simple weighting scheme and maximizing the use of idle listening periods. By identifying local minima nodes, it also has the potentiality of reducing route failure by 70% when utilized as a routing support.
    2012 International Symposium on Telecommunication Technologies (ISTT); 01/2012

Full-text (2 Sources)

View
0 Downloads
Available from
Jun 24, 2014