PAPR reduction of LOFDM signals with an efficient nonlinear companding transform

One of the major drawbacks remain unsolved in lattice orthogonal frequency division multiplexing (LOFDM) system is its high peak-to-average power ratio (PAPR). In this paper, a modified nonlinear companding transform scheme is proposed. By dealing with the companding transform and signal power independently when transform the Gaussian-distributed LOFDM signals into a desired piecewise function, a great more design flexibility can be achieved to satisfy various system requirements along with a relatively low complexity. The theoretical analysis regarding the transform gain and the selection criteria of corresponding companding parameters are also derived. Moreover, numerous simulations demonstrate that the modified piecewise method can also obtain a well trade-off between PAPR reduction and bit error ratio (BER) performance.