Sidelobe Suppression in OFDM-based cognitive radio systems

Orthogonal frequency division multiplexing (OFDM) suffers from significant out-of-band radiation due to high sidelobes of modulated subcarriers. In a cognitive radio (CR) system this effect results in high interference between secondary and primary users (PUs). Existing methods for reducing this interference have the drawbacks of significant data transmission rate reduction or power peak to average ratio (PAPR) growth. In this paper an adaptive optimal method is proposed that treats on OFDM signal in both time and frequency domains. Simulation results show that by using this algorithm, it is possible to achieve a high value of sidelobe suppression while the PAPR value of the transmitted signal is unchanged and the transmission rate reduction is lower than similar methods.