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...etween spectrum congestion and spectrum under-utilization, cognitive radio has been recently considered as an efficient approach to improve the spectrum utilization via opportunistic spectrum sharing =-=[2]-=-. However, cognitive radios are considered lower priority to a PU. This fundamental requirement is to avoid interference to potential PUs in their vicinity. To implement without interference to the pr...

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...rawback of a matched filter is that it needs the prior knowledge of the primary user’s signal such as the modulation type and order, pulse shaping and packet format. Cyclostationary feature detection =-=[4]-=- can detect the signals with very low SNR but still requires some prior knowledge of the PU. Another shortcoming is that its computational complexity is a bottleneck for its implementation. As all the...

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...mplexity is a bottleneck for its implementation. As all the frequencies should be searched in order to generate the spectral correlation function, the calculation complexity is huge. Energy detectors =-=[5]-=- are the most common way of spectrum sensing because of their low computational complexity. However, it is well-known that such a method lacks the capability to differentiate different signal types. T...

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... , the detection probability PdMSD , over AWGN can be obtained as P ⎡ ⎛ 2γ λ ⎞⎤ = 1−⎢1 −Q , ⎥ ⎢ ⎜ δ δ ⎟ ⎣ ⎝ A ⎠⎥⎦ dMSD , 1 L (16) Since the signal strength follows a Rician distribution f γ , will be =-=[10]-=- in such scenario, the pdf of SNR, ( ) Ric 329( K + 1) γ ⎞ ⎛ K( K + 1) K + 1 ⎛ γ ⎞ fRic ( γ )= exp⎜−K − ⎟I 0 2 γ ⎝ γ ⎠ ⎜ γ ⎟ ⎝ ⎠ (17) 2 2 where ( 2δ A ) K = A , which is the Rician factor. For K=0, t...

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...ied as matched filter, cyclostationary feature detection and energy detection. The matched filter is viewed as optimal since it maximizes received signal-to-noise ratio (SNR) in communication systems =-=[3]-=-. However, a significant drawback of a matched filter is that it needs the prior knowledge of the primary user’s signal such as the modulation type and order, pulse shaping and packet format. Cyclosta...

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...potheses can be approximated by Gaussian distributions, which are given by (9). Thus, under hypothesis 0 H and H 1 , the envelope of M x ( t ) , r , are respectively Rayleigh and Rician T distributed =-=[9]-=- 0 2 δ A 2 r − 2 2δ A r pr ( : H) = e r≥ 0 (10) 2 2 ( r A ) r ⎡ + ⎤ ⎛ Ar⎞ p( r: H1) = exp ⎢− ⎥I 2 2 0⎜ , A 0, r 0 2 ⎟ ≥ ≥ (11) δA ⎢ 2δA ⎥ ⎝δ ⎣ ⎦ A ⎠ 2 2 where δA= δ ( 2N+ 1) . I0 () . is the zeroth-or...