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Nowadays, Cognitive Radio (CR) is projected as the technology that will maximize the utilization of the spectrum resources in next generation wireless systems. Therefore, the Spectrum Sensing (SS) is the key function, which allows CR to know the available spectrum resources of an interest band. Nevertheless, one of the major problems in the SS is the big amount of samples that are processed in the...
In this paper, a novel wideband spectrum sensing algorithm based on Compressive Sensing (CS) and reconstruction of second order signal statistics from covariance matrix of the acquired samples for Cognitive Radio (CR) systems is presented. This allows cognitive users to sense the spectrum without apriori knowledge of signal characteristics in the radio environment by minimizing the amount of samples...
Accurate wideband spectrum sensing and primary user detection with high probability in low SNR condition is critical in cognitive radio systems. In these systems, usually, the bandwidth of the spectrum to be sensed is very wide but the spectrum occupancy is very low. Complexity of conventional wideband spectrum sensing methods can be very high, due to a very high sampling rate that is needed. In compressive...
Wideband spectrum sensing is a challenging task due to the constraints of digital signal processing (DSP) unit using in extant wireless systems. Compressive sensing (CS) is a new paradigm in signal processing, chosen for sparse wideband spectrum estimation with compressive measurements, thus provides relief of high-speed DSP requirements of cognitive radio (CR) receivers. In CS, whole wideband spectrum...
A digital baseband cognitive radio spectrum sensing processor with 200-kHz resolution over 200-MHz bandwidth is integrated in 1.64 mm in 65-nm CMOS. The processor uses adaptive channel-specific threshold and sensing time to achieve detection probability 0.9 and false-alarm probability 0.1 for 5-dB SNR and adjacent-band interferers of 30-dB INR within a 50-ms sensing time....
Spectrum sensing over a wide bandwidth increases the probability of finding unutilized spectrum for cognitive radios. However, energy-efficient VLSI realization of wideband sensing algorithms is challenging due to complex signal processing and real-time requirement. In addition, strong primary users introduce spectral leakage in adjacent unused bands, resulting in sensing performance degradation....
For systems and devices, such as cognitive radio and networks, that need to be aware of available frequency bands, spectrum sensing has an important role. A major challenge in this area is the requirement of a high sampling rate in the sensing of a wideband signal. In this paper a wideband spectrum sensing method is presented that utilizes a sub-Nyquist sampling scheme to bring substantial savings...
Beside providing solutions to the interoperability problem of the first responders, location awareness feature of the cognitive radios can be beneficial for victim and first responder location estimation under extreme conditions. Location and environment based services can be employed to detect and locate victims even when the core wireless communications networks are down. In this paper, a location...
For cognitive radios (CRs), compressive sampling (CS) techniques have been utilized for spectrum sensing in order to alleviate the high signal acquisition costs in the wideband regime. Given the desired sensing performance, the fundamental limit on the sampling rates is determined by the actual sparsity order Snz of the signal spectrum, which can be considerably lower than the Nyquist sampling rate...
In this paper, a novel power spectrum density (PSD) estimation approach is proposed for accurate and efficient wideband spectrum sensing in Cognitive Radio (CR) systems. Based on the observed signal from a wideband receiver, the goal of determining the fluctuation-free signal PSD is formulated as a constrained Bayesian estimation problem, subject to spectral variation constraints between neighboring...
The source line fitting method (SLFM) is effective for estimating DOAs of wideband signals, when the inter-element spacing of the array exceeds half the wavelength. It exploits one reference to construct source lines (SL), and estimates DOAs by measuring the angles of SLs. In this paper, we improve SLFM by using two reference signals, which is called two references SLFM (TRSLFM). The incremental reference...
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