ABSTRACT:
A major drawback of orthogonal frequency division Multiplexing (OFDM) is the high Peak-to-Average Power Ratio (PAPR) of the transmitted signal. In this paper, we propose a novel method to reduce the PAPR in an OFDM signal. This novel proposed method from now onwards will be known as Peak-Inversion Technique (PIT), which is based on the inversion of the peaks in the transmitted OFDM signal beyond a certain threshold value. Inversion of peaks of OFDM signal is done by folding the higher amplitudes of OFDM signal those are above the optimized threshold levels towards the lower amplitude of OFDM signal. The optimized threshold levels are chosen in a manner such that they lie at same value, above and below the reference axis of the signal, and when the peaks are folded they do not become the peaks in the opposite direction. Peak-Inversion Technique presented in this paper reduces the PAPR by more than 3.2 dB for the quadrature phase shift keying (QPSK) modulation. Also the symbol error probability curve presented for the PAPR reduced OFDM signal is very close to the theoretical symbol error probability curve of the OFDM signal. In this paper all the results are obtained from commercial available Matlab simulation software.