In this paper, an adaptive near-far resistant detector using a multiple antennas for acquiring synchronization of an asynchronous DS-CDMA system is presented. The only requirement is the prior knowledge of the user-spreading sequence of interest. Also, there is no need of a training sequence and a training period. Synchronization acquisition of asynchronous DS-CDMA signals is treated as a binar...

In this paper, we propose a new approach for the detection of OFDMA and other wideband signals in the context of centralized cooperative spectrum sensing for cognitive radio (CR) applications. The approach is based on the eigenvalues of the received signal covariance matrix whose samples are in the frequency domain. Soft combining of the eigenvalues at the fusion center is the main novelty. Thi...

The problem of detecting the number of uncorrelated narrowband signals received by an array of sensors when the direction of arrival (DOA) and power level of each source is unknown is investigated. A multi-hypothesis generalized likelihood ratio test (GLRT) approach is used, resulting in a procedure which maximizes the likelihood function with respect to the number of signals and their DOAs and...

In this fast communication, we derive the statistical resolution limit (SRL), characterizing the minimal parameter separation, to resolve two closely spaced known near-field sources impinging on a linear array. Toward this goal, we conduct on the first-order Taylor expansion of the observation model a Generalized Likelihood Ratio Test (GLRT) based on a Constrained Maximum Likelihood Estimator (...

Signal amplitude estimation and detection from unlabeled quantized binary samples are studied, assuming that the order of the time indexes is completely unknown. First, maximum likelihood (ML) estimators are utilized to estimate both the permutation matrix and unknown signal amplitude under arbitrary, but known signal shape and quantizer thresholds. Sufficient conditions are provided under whic...

We develop a new passive image formation method capable of exploiting information about multiple scattering in the environment, as well as statistics of the objects to be imaged, additive noise and clutter, using measurements from a sparse array of receivers that rely on illumination sources of opportunity. The array of receivers can be distributed spatially in an arbitrary fashion with several...

The implementation of the generalized detector (GD) in cognitive radio (CR) systems allows us to improve the spectrum sensing performance in comparison with employment of the conventional detectors. We analyze the spectrum sensing performance for the uncorrelated and spatially correlated receive antenna array elements. Additionally, we consider a practical case when the noise power at the outpu...

We propose to improve the performance of a generalized coherence (GC) detector using noise-suppressed estimates obtained from time varying (TV) techniques. In source detection and localization, the presence of a common but unknown signal must be detected using data from several noisy channels. If one of the channel outputs has a sufficiently high SNR, then it could be pre-processed to improve d...

This paper considers a novel fusion rule for spectrum sensing scheme for a cognitive radio network with multi-antenna receivers. The proposed scheme exploits the fact that when any primary signal is present, measurements are spatially correlated due to presence of inter-antenna and inter-receiver spatial correlation. In order to exploit this spatial structure, the generalized likelihood ratio t...