“…To use the frequency spectrum more efficiently, those spectrum holes can be used by the SUs with lower priorities in an opportunistic manner such that the interference from SUs to PUs is negligible or is kept below a predetermined threshold. To share the spectrum in the CR system, the SUs may require the spectrum‐sensing capability to sense and detect the absence and presence of PUs in the frequency spectra and find a spectrum hole to use it [1, 2, 4–6]. So far, there have been several spectrum‐sensing schemes presented in the literature, such as energy detection, matched filter detection etc.…”