TY - CONF T1 - Locally optimal invariant detector for testing equality of two power spectral densities T2 - IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) Y1 - 2018 A1 - David Ramírez A1 - Daniel Romero A1 - Javier Vía A1 - R. López-Valcarce A1 - Ignacio Santamaría KW - cognitive radio KW - winter AB -
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.
JF - IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) CY - Calgary, Canada ER - TY - JOUR T1 - Testing equality of multiple power spectral density matrices JF - IEEE Trans. Signal Processing Y1 - 2018 A1 - David Ramírez A1 - Daniel Romero A1 - Javier Vía A1 - R. López-Valcarce A1 - Ignacio Santamaría KW - cognitive radio KW - winter VL - 66 IS - 23 ER - TY - JOUR T1 - Detection of Rank-P Signals in Cognitive Radio Networks With Uncalibrated Multiple Antennas JF - IEEE Trans. on Signal Processing Y1 - 2011 A1 - David Ramírez A1 - Gonzalo Vázquez-Vilar A1 - R. López-Valcarce A1 - Javier Vía A1 - Ignacio Santamaría KW - cognitive radio KW - dynacs KW - spectrum sensing AB -
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.
VL - 59 IS - 8 ER - TY - CONF T1 - Multiantenna detection under noise uncertainty and primary user's spatial structure T2 - IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) Y1 - 2011 A1 - David Ramírez A1 - Gonzalo Vázquez-Vilar A1 - R. López-Valcarce A1 - Javier Vía A1 - Ignacio Santamaría KW - cognitive radio KW - generalized likelihood ratio test (GLRT) KW - spectrum sensing JF - IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) PB - IEEE CY - Prage, Czech Republic ER - TY - CONF T1 - Multiantenna spectrum sensing: detection of spatial correlation among time-series with unknown spectra T2 - IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) Y1 - 2010 A1 - David Ramírez A1 - Javier Vía A1 - Ignacio Santamaría A1 - R. López-Valcarce A1 - L. L. Scharf KW - cognitive radio KW - coherence spectrum KW - generalized likelihood ratio test KW - Hadamard ratio KW - multiple-channel signal detection JF - IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) CY - Dallas, TX ER -