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In chaos secure communication system, to separate effectively chaos and harmonic signal is an important way of testing systematic confidential performance. In recent years, the time-frequency analysis theory is more and more mature, effective time-frequency analytical algorithms are emerging constantly. The paper starts with the time-frequency character analysis of the chaos, the noise and the harmonic...
The separation of chaos and signal is an important problem of chaos signal processing. In recent years, the time-frequency analysis method is more and more mature. This paper starts with the time-frequency character analysis of the chaotic signal, the noise and the harmonic signal. It also discusses the influence of the amplitude, frequency of harmonic signal and the signals to noise ratio (SNR) on...
Spectrum sensing is the key technology in Cognitive Radio (CR) for primary user detection. Noise uncertainty in spectrum sensing will make the detector unreliable due to "SNR walls". In this paper, cooperative spectrum sensing with adaptive thresholds is proposed to improve the detection performance under noise uncertainty. In this algorithm, each secondary user will use a two-thresholds...
We discuss the spectrum sensing problem which is crucial in opportunistic spectrum access. An In-band spectrum sensing method based on linear self-signal elimination is proposed. In this method, quiet period is not needed so that transmission performance can be improved without the interruption of on-going transmission. According to the AR model of the wireless fading channel, the adjacent symbols...
Wireless ad hoc networks are expected to provide broadband services parallel to their wired counterparts in near future. To address this need, MIMO (multiple-input-multiple-output) antenna techniques hold significant promise. Most previous work on capacity analysis of ad hoc networks is based on an implicit assumption that each link exclusively occupies a geometric area, referred to as exclusion region...
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