Modified μ-Law Companding Transform for PAPR Reduction in SC-FDMA Systems

Abstract

Low peak-to-average power ratio (PAPR) enabled single carrier frequency division multiple access (SC-FDMA) to be implemented in long-term evolution uplink communications. But there is a need to lessen PAPR as SC-FDMA systems when used in localized subcarrier mapping exhibit high PAPR for higher order modulations. Companding is a simple technique to minimize PAPR without side information. It has very low implementation complexity. μ-Law companding, which is one of the most popularly used companding transforms, provides significant PAPR reduction but increases the average signal power. In this paper, we come up with a modified μ-law companding transform without any decompanding operation at the receiver side, which do not increase the average signal power after companding. Simulation results demonstrate that the PAPR reduction achieved by modified μ-law companding technique is same as that of conventional μ-law technique. Modified μ-law companding provides similar bit error rate (BER) performance as that of conventional μ-law companding technique when AWGN channel is considered while it surpasses the conventional technique when Veh-A channel is considered. The proposed technique also has better power spectral density (PSD) performance when compared to conventional technique.