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This paper presents a novel frequency-domain energy detection scheme based on extreme statistics for robust sensing of OFDM sources in the low SNR region. The basic idea is to exploit the frequency diversity gain inherited by frequency selective channels with the aid of extreme statistics of the differential energy spectral density (ESD). Thanks to the(More)
This paper presents a novel differential energy detection scheme for multi-carrier systems, which can form fast and reliable decision of spectrum availability even in very low signal-to-noise ratio (SNR) environment. For example, the proposed scheme can reach 90% in probability of detection (PD) and 10% in probability of false alarm (PFA) for the SNRs as(More)
This paper presents a novel pilot-assisted spectrum sensing technique for orthogonal frequency-division multiplexing (OFDM) systems. The main idea is based upon the physical nature that subcarriers carrying pilots or payload data have different first-order and second-order statistical properties. These differences vanish when the spectrum of interest is(More)
Spectrum sensing is one of key enabling techniques to advanced radio technologies such as cognitive radios and ALOHA. This paper presents a novel non-cooperative spectrum sensing approach that can achieve a good trade-off between latency, reliability and computational complexity. Our major idea is to exploit the first-order cyclostationarity of the primary(More)
Due to its special coordination ability to Cu(II)-terpyridine complexes, a simple and straightforward visual recognition of p-DMAP out of its analogues has been realized via selective metallogel collapse. In combination with the selective gel collapse and the self-healing properties of metallohydrogel , its potential application towards chemo-switch is also(More)
OBJECTIVE To investigate the effects of unrepaired cleft palate on the development of vocabulary comprehension and expression of Chinese children aged 8 to 15 months. METHODS The parents or caregivers of 40 infants with unrepaired cleft palate were recruited from the Cleft Lip and Palate Center at the Stomatology School of Peking University. Vocabulary(More)
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