Interference reduction in Cognitive radio networks using Genetic and Firefly Algorithms

Cognitive radio (CR) is the novel technology in wireless communication, which has an ability to use the vacant spectrum of primary user smartly. Non Contiguous orthogonal frequency division multiplexing (NCOFDM), a multicarrier system is considered as the appropriate candidate for CR physical layer, but due to its high sidelobes it suffers from high out of band (OOB) radiation, that can affect its spectrum sharing capability. In this paper, we proposed two search algorithms: Genetic Algorithm (GA) and Firefly algorithm (FFA) for estimating the amplitudes of the Cancellation subcarriers (CCs). These CCs are inserted on either side of the used NCOFDM signal to cancel the sidelobes. Simulation results show that better sidelobe reduction is achieved by the proposed algorithms as compared to the existing techniques in the literature.