A Companding Scheme for Reducing PAPR of Optical OFDM Signals

In VLC systems which adopt OFDM technology, system performances deteriorate because of high PAPR. If traditional nonlinear companding schemes are directly applied into the optical OFDM system, bit error rate will be high. A new nonlinear companding technique is proposed to change the probability density function of OFDM signals from conforming normal distribution to linear piecewise function. Both theoretical derivation and performance analysis show that when compared with former typical companding scheme, the new scheme has the same effects of reducing PAPR and better BER performance. These results are also verified by Matlab simulation.