A trellis based PAPR reduction method for OFDM

A new coding-based technique is proposed to reduce the peak-to-average power ratio (PAPR) of an OFDM system. The method is based firstly on the calculation of the PAPR values of all symbol output sequences for the same input data sequence in an OFDM frame, obtained by considering all possible initial states on the TCM trellis diagram, and then the transmission of the output sequence with the lowest PAPR value. Increasing the number of trellis states increases both the PAPR reduction and coding gains, thanks to the increased redundancy, the price paid being the increased number of PAPR calculations before transmission. Contrary to coding-based PAPR reduction techniques given in the literature, this method avoids the transmission of any side information to recover the original data at the receiver, but the error performance is slightly degraded due to the suboptimum operation of the Viterbi decoder.