An efficient joint algorithm for reducing PAPR of SC-FDMA system in cognitive radio networks

Cognitive radio (CR) has been proposed as a solution for the spectrum scarcity problem. This paper investigates single-carrier frequency division multiple access (SC-FDMA) for cognitive radios. Recently, SC-FDMA has been suggested as a candidate for multicarrier based CR systems. In this paper, we propose enhanced techniques to reduce the peak to average power ratio (PAPR) in SC-FDMA for Cognitive Radio Network (CRN). We start by showing the effect of two standard PAPR reduction techniques (interleaver based and selective mapping) to reduce the PAPR in SC-FDMA based CR. Then, a proposed joint algorithm interleaver with selective mapping in a way that is suitable for SC-FDMA based CR will be proposed that results in a lower PAPR than using them individually. Simulation results show that the SC-FDMA with proposed techniques has a lower PAPR when compared with the conventional SC-FDMA system for CRN, while the complexity of the system slightly increases. Results also reveal that the no. of interleavers and SLM sequences must be chosen carefully in order to limit the PAPR with slightly increases in the complexity of the system.