153 research outputs found
Canonical correlation analysis of high-dimensional data with very small sample support
This paper is concerned with the analysis of correlation between two
high-dimensional data sets when there are only few correlated signal components
but the number of samples is very small, possibly much smaller than the
dimensions of the data. In such a scenario, a principal component analysis
(PCA) rank-reduction preprocessing step is commonly performed before applying
canonical correlation analysis (CCA). We present simple, yet very effective
approaches to the joint model-order selection of the number of dimensions that
should be retained through the PCA step and the number of correlated signals.
These approaches are based on reduced-rank versions of the Bartlett-Lawley
hypothesis test and the minimum description length information-theoretic
criterion. Simulation results show that the techniques perform well for very
small sample sizes even in colored noise
LMPIT-inspired Tests for Detecting a Cyclostationary Signal in Noise with Spatio-Temporal Structure
In spectrum sensing for cognitive radio, the presence of a primary user can
be detected by making use of the cyclostationarity property of digital
communication signals. For the general scenario of a cyclostationary signal in
temporally colored and spatially correlated noise, it has previously been shown
that an asymptotic generalized likelihood ratio test (GLRT) and locally most
powerful invariant test (LMPIT) exist. In this paper, we derive detectors for
the presence of a cyclostationary signal in various scenarios with structured
noise. In particular, we consider noise that is temporally white and/or
spatially uncorrelated. Detectors that make use of this additional information
about the noise process have enhanced performance. We have previously derived
GLRTs for these specific scenarios; here, we examine the existence of LMPITs.
We show that these exist only for detecting the presence of a cyclostationary
signal in spatially uncorrelated noise. For white noise, an LMPIT does not
exist. Instead, we propose tests that approximate the LMPIT, and they are shown
to perform well in simulations. Finally, if the noise structure is not known in
advance, we also present hypothesis tests using our framework
Two-Channel Passive Detection Exploiting Cyclostationarity
This paper addresses a two-channel passive detection problem exploiting
cyclostationarity. Given a reference channel (RC) and a surveillance channel
(SC), the goal is to detect a target echo present at the surveillance array
transmitted by an illuminator of opportunity equipped with multiple antennas.
Since common transmission signals are cyclostationary, we exploit this
information at the detector. Specifically, we derive an asymptotic generalized
likelihood ratio test (GLRT) to detect the presence of a cyclostationary signal
at the SC given observations from RC and SC. This detector tests for different
covariance structures. Simulation results show good performance of the proposed
detector compared to competing techniques that do not exploit
cyclostationarity
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