Author : Sonali K.Deshmukh and S. D. Chavan

Orthogonal frequency division multiplexing (OFDM) is form of multi-carrier modulation technique. Due to its advantages of high spectral efficiency, robustness to multipath fading effects, immunity to impulse interference are among the property of OFDM. However, one the major drawback of OFDM is very high peak-to-average power ratio (PAPR).Number of techniques has been proposed in literature for reducing the PAPR in OFDM systems. Among the various PAPR reduction techniques, in this paper the non-linear companding scheme is proposed to reduce the PAPR and improve Bit Error Rate(BER) for OFDM systems. The Nonlinear Companding Transform (NCT) distortion technique is proposed for reducing the high Peak –To –Average Power Ratio This proposed scheme reduces the PAPR by compressing the peak signals and expanding the small while maintaining average power constant selecting transform parameters . Finally, simulation results show that the proposed scheme in terms of spectrum side-libes, PAPR reduction and BER performance

Keywords: Orthogonal frequency Division Multiplexing (OFDM), Peak-to-Average Power Ratio(PAPR), Nonlinear Companding Transform (NCT).