Pre- and post-IFFT PAPR reduction in pilot-aided OFDM transmission systems

In this paper we propose a scheme that can be deployed in practical multi-carrier (OFDM) transmission systems offering a reduced peak-to-average power ratio (PAPR). In general, the PAPR reduction can either be applied prior to the IFFT process or after it. This scheme is based on unitary-matrix transformation (UMT) of the input vector to the IFFT. This means that the transmission chain can further benefit from a suitable post-IFFT PAPR reduction algorithm. For the evaluation of the proposed scheme, we have used DVB-T2, a world-known second generation digital transmission standard. The paper describes the PAPR performance gains when UMT is applied to a DVB-T2 simulation platform with and without its two standard post-IFFT PAPR algorithms, namely Tone Reservation (TR) and Active Constellation Extension (ACE). The paper provides the Complimentary Cumulative Distribution Functions (CCDF) curves, Bit Error Rate (BER) curves, average signal powers (before and after PAPR reductions), Power Spectral Density (PSD) plots.