The demand for wireless services is on the rise and the vast majority of the spectral resources have already been licensed. Consequently, cognitive radio technology has been proposed to make secondary use of licensed spectrum. Multicarrier communication technology has been suggested to utilize the white space on the spectrum. Orthogonal frequency-division multiplexing (OFDM) was the first multicarrier technique proposed for cognitive radio. However, OFDM suffers from significant leakage among the carriers of different users. On the other hand, orthogonal frequency-division multiplexing Quadrature amplitude with offset communication can overcome the spectral leakage. Therefore, orthogonal frequency-division multiplexing with offset Quadrature amplitude modulation (OFDM / OQAM) has been suggested as an alternative to OFDM for cognitive radios.