JISE

    The purpose of cognitive radio (CR) is to defend the transmission of licensed (primary) user in the presence of unlicensed (cognitive) users within the same spectral vicinity. Non-contiguous orthogonal frequency division multiplexing (NC-OFDM) is a favorable and practical methodology of attaining wireless data transmission which is spectrally dexterous. It portrays an effective approach for Cognitive users (CU's) to access patchy spectral openings. One of the major drawbacks of NC-OFDM is interference to the neighboring wireless channels due to the high sidelobes. This paper highlights perspective approaches i.e. Genetic algorithm (GA) and Differential evolution (DE) for the sidelobe power reduction of NC-OFDM signals. The proposed algorithms estimate the levels of cancellation carriers (CCs) to reduce the out of band radiation (OOB) emissions. The fitness function is based on linear least square error which requires single snapshot. The cogency and usefulness of the proposed schemes are verified extensively through Monte Carlo simulations. The results are compared with the Brandes CC and Ahmed selim Advance cancellation carrier (ACC), Ahmed selim Advance Subcarrier weighting (ASW) technique. The proposed scheme produces competitive results and significantly reduces the sidelobe levels.