Summary form only given, as follows. One of the main limitations of OFDM systems is that it exhibits high Peak to Average Power Ratio (PAPR). It is desirable to reduce it as high PAPR causes saturation in power amplifiers thus leading to inter-modulation products among the sub carriers. In this paper two efficient and distortion-less schemes for PAPR reduction, Selected Mapping (SLM) and Partial Transmit Sequences (PTS), are described and compared. Both these schemes introduce some additional complexity but nearly vanishing redundancy. These approaches are very flexible and can work with arbitrary number of sub carriers and type of constellation mapping used. Both these methods use the transformation of constellation.