Crest Factor Reduction in Multicarrier Transmission by Low Crest Mapping

Orthogonal frequency division multiplexing (OFDM) has several properties which makes it an attractive modulation technique for high speed data transmission. However one major disadvantage of OFDM is that the time domain OFDM signal which is a sum of several sinusoids leads to a high peak-to-average power ratio (PAPR). High PAPR can cause non linear distortion of the signal at the transmitter (in-band and out-of-band distortion). Number of techniques have been proposed in the literature for the reduction of the high PAPR of the OFDM signal. But most of these techniques are unable to achieve simultaneously a large reduction in PAPR, with low complexity, with low coding overhead and without performance degradation. In this paper a new technique 'low crest mapping (LCM)' is proposed for reduction of PAPR in OFDM Systems. This new technique is a simple and novel one without any increase in bandwidth and no in-band and out-of-band distortions apart from its simplicity. Simulation results show a considerable reduction in the PAPR when the low crest mapping (LCM) is applied to a sample of four/eight sub carriers with BPSK modulation