Interference Prevention in Cognitive Radio Networks

Orthogonal frequency division multiplexing (OFDM), an encouraging technology for accessing spectrum, and white spaces dynamically because of its ability to shape its transmitted spectrum according to the specific environment. However, the sidelobes of the transmitted OFDM spectrum can cause significant interference to neighboring users, especially in an OFDM-based cognitive radio environment, where unlicensed users can opportunistically access white holes of the spectrum. In this paper, we have proposed two different interference preventing techniques. The proposed techniques are hybridizing the generalized sidelobe canceler with cancellation carriers' technique, whose amplitude is estimated using differential evolution algorithm and Cuckoo search algorithm. The effectiveness and reliability of the proposed techniques are demonstrated with the help of computer simulations in terms of power spectral density, showing that better interference prevention is achieved compared to existing techniques found in the literature.