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Cognitive radio is a potential technology for increasing spectral efficiency in wireless communications systems, where in a hypothetical future overlay policy, secondary cognitive radios temporarily use spectrum that is not utilized, as long as negligible impact is caused to primary licensed users. Dependable spectrum sensing is needed to overcome the hidden node problem that arises when a primary...
Cognitive radio is a promising solution to the problem of spectrum scarcity by means of allowing secondary radio networks access the spectrum opportunistically. One of the most important issues in cognitive radio is how to detect existing over-the-air signals reliably. Not a few literatures have reported that signals could be detected via their inherent or embedded properties. However, these may not...
Spectrum sensing is the key function of cognitive radios which act as secondary users and dynamically access vacant frequency bands. In practice, this sensing function is fulfilled by detecting the existence of primary users' signals. Almost all modulated signals show cyclostationarity characteristics which are suitable for signal detection. Some specific signals (e.g. Interleaved Frequency Division...
Cognitive networks can potentially solve the problems of spectrum scarcity by accommodating unlicensed (secondary) users in under-utilized segments of the spectrum. Spectrum sensing serves as the primary stimulus for a cognitive radio and is vitally important for ensuring that the unlicensed users do not offer intolerable levels of interference to licensed (primary) users. Cooperative spectrum sensing...
Cognitive radio is an enabling technology, which is expected to lead to a more efficient utilization of the available spectral resources due to its flexibility and its ability to sense its spectral environment. Recently, spectrum sensing methods based on exploiting the cyclostationary characteristics of communication signals have been drawing interest. In practice, imperfections in the signal generation...
Cognitive radio is an enabling technology, which is expected to lead to a more efficient utilization of the available spectral resources due to its flexibility and its ability to sense its spectral environment. Recently, spectrum sensing methods based on exploiting the cyclostationary characteristics of communication signals have been drawing considerable interest. Imperfections in the cognitive radio...
We present a compressive wide-band spectrum sensing scheme for cognitive radios. The received analog signal at the cognitive radio sensing receiver is transformed in to a digital signal using an analog-to-information converter. The autocorrelation of this compressed signal is then used to reconstruct an estimate of the signal spectrum. We evaluate the performance of this scheme in terms of the mean...
Cognitive radios should have the capability to detect idle spectrum and share it without harmful interference with other users. This paper presents a strategy for extracting second-order cyclostationary characteristics of licensed system and rental system signals based on spectrum pooling system. According to cyclostationary characteristics of licensed users signals received at the nodes of CRs, predicting...
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