Improved PAPR Reduction Using Gamma Correction in SC-FDMA Systems Under Multipath Fading Channels

Single-carrier frequency division multiple access (SC-FDMA) has become one of the most attractive standards for next-generation wireless communication systems. However, in the presence of carrier frequency offset (CFO), SC-FDMA suffers from inter-carrier interference (ICI) and multiple access interference (MAI). In addition, peak-to-average power ratio (PAPR) disrupts the system performance whenever non-linear power amplifiers are used. This paper studies a companding scheme constructed using gamma correction to reduce PAPR in the SC-FDMA system. The proposed gamma correction companding (GCC) for the SC-FDMA system outperforms the existing PAPR reduction techniques such as clipping, mu-law companding, and hybrid techniques. In addition, we investigate existing CFO compensation schemes and the significance of minimum mean square error (MMSE) equalization and parallel interference cancellation (PIC) in reducing MAI and ICI under severe multipath fading channels. The simulation results reveal that the proposed GCC-based scheme significantly reduces PAPR compared to conventional companding techniques. Further, using MMSE based CFO compensation schemes combined with PIC is also investigated along with the proposed GCC-based system to reduce MAI and PAPR for uplink SC-FDMA systems without significant degradation in system performance.