Generalized M-2M Mapping Scheme for SLM and PTS Based OFDM Systems Without Side-Information

Abstract

Orthogonal frequency division multiplexing (OFDM) is an attractive multicarrier modulation scheme, but it suffers from the problem of high peak-to-average power ratio (PAPR). Selected mapping (SLM) and partial transmit sequences (PTS) are two well known, distortion-less techniques with good PAPR reduction capabilities. But, both the methods require side information (SI) about the phase rotation factors to recover the original data signal at the receiving end. The transmission of SI not only results in data rate loss but also, in BER performance degradation if SI gets corrupted over the channel. In this paper we have proposed a new mapping scheme, named “$M\text{- }2M$ Mapping scheme” for SLM and PTS based methods to completely eliminate the requirement of SI at the receiver. In this scheme $M$ data points are mapped to the constellation points of 2M-ary modulation scheme using (1, j) as the phase rotation factors. Some criteria are suggested with which the method is applied for different constellation sizes, $M=4$ to $M=16$. The method can be easily coupled with conventional SLM and PTS techniques. When compared with the existing methods like multi point square mapping, which do not need SI, our technique is scalable and provides good PAPR reduction capability with consistent BER performance.