%0 Conference Paper %B IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) %D 2018 %T Locally optimal invariant detector for testing equality of two power spectral densities %A David Ramírez %A Daniel Romero %A Javier Vía %A R. López-Valcarce %A Ignacio Santamaría %K cognitive radio %K winter %X
This work addresses the problem of determining whether two multivariate random time series have the same power spectral density
(PSD), which has applications, for instance, in physical-layer security and cognitive radio. Remarkably, existing detectors for this
problem do not usually provide any kind of optimality. Thus, we study here the existence under the Gaussian assumption of optimal
invariant detectors for this problem, proving that the uniformly most powerful invariant test (UMPIT) does not exist. Thus, focusing on
close hypotheses, we show that the locally most powerful invariant test (LMPIT) only exists for univariate time series. In the multivariate
case, we prove that the LMPIT does not exist. However, this proof suggests two LMPIT-inspired detectors, one of which outperforms
previously proposed approaches, as computer simulations show.
%B IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) %C Calgary, Canada %G eng %0 Journal Article %J IEEE Trans. Signal Processing %D 2018 %T Testing equality of multiple power spectral density matrices %A David Ramírez %A Daniel Romero %A Javier Vía %A R. López-Valcarce %A Ignacio Santamaría %K cognitive radio %K winter %B IEEE Trans. Signal Processing %V 66 %P 6268-6280 %8 12/2018 %G eng %N 23 %R 10.1109/TSP.2018.2875884 %0 Journal Article %J IEEE Trans. on Signal Processing %D 2011 %T Detection of Rank-P Signals in Cognitive Radio Networks With Uncalibrated Multiple Antennas %A David Ramírez %A Gonzalo Vázquez-Vilar %A R. López-Valcarce %A Javier Vía %A Ignacio Santamaría %K cognitive radio %K dynacs %K spectrum sensing %X
Spectrum sensing is a key component of the Cognitive Radio paradigm. Typically, primary signals have to be 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.
%B IEEE Trans. on Signal Processing %V 59 %P 3764-3774 %8 08/2012 %G eng %N 8 %R 10.1109/TSP.2011.2146779 %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2011 %T Multiantenna detection under noise uncertainty and primary user's spatial structure %A David Ramírez %A Gonzalo Vázquez-Vilar %A R. López-Valcarce %A Javier Vía %A Ignacio Santamaría %K cognitive radio %K generalized likelihood ratio test (GLRT) %K spectrum sensing %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %I IEEE %C Prage, Czech Republic %P 2948-2951 %8 May %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2010 %T Multiantenna spectrum sensing: detection of spatial correlation among time-series with unknown spectra %A David Ramírez %A Javier Vía %A Ignacio Santamaría %A R. López-Valcarce %A L. L. Scharf %K cognitive radio %K coherence spectrum %K generalized likelihood ratio test %K Hadamard ratio %K multiple-channel signal detection %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %C Dallas, TX %G eng