Two-piecewise companding transform for PAPR reduction of OFDM signals

To reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals, a two-piecewise companding (TPWC) transform is proposed so as to compress large signal amplitudes and expand small ones with two different linear functions. The TPWC transform can provide significant PAPR reduction with low computational complexity, which is similar to other existing linear transforms. Besides, a good trade-off between PAPR reduction and bit-error-rate (BER) performances can be achieved by carefully choosing the three parameters in the proposed scheme. A good power spectral density (PSD) performance can also be achieved, since there are no inflexion points in the resulting profile. The idea of the two-piecewise transform can be extended to other nonlinear functions.