Iterative companding transform and filtering for reducing PAPR of OFDM signal

In this paper, an efficient Iterative Companding Transform and Filtering (ICTF) technique is proposed for reducing the Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) signal. By means of a specially designed iterative procedure, ICTF is able to obtain both an improved Bit Error Rate (BER) and minimized Out-of-Band Interference (OBI) while reducing the PAPR significantly. A comprehensive theoretical analysis is presented, and some important results such as the achievable PAPR gain, impact of companding distortion, and selection criteria for companding parameters and maximum iteration number are derived. In particular, it is shown that the ICTF without de-companding at the receiver can offer a good BER performance. Simulations show that compared to the classic Iterative Clipping and Filtering (ICF) technique, ICTF can dramatically decrease the number of required iterations to reach the desired PAPR with low complexity. In addition, the companded OFDM symbols by the proposed ICTF technique have less in-band distortion, and lower out-of-band spectral regrowth than traditional companding schemes.