A New OFDM System Based on Companding Transform Under Multipath Channel

Companding technology has been widely used for reducing PAPR of orthogonal frequency division multiplexing (OFDM) system, because of it low implementation complexity and the simple realization. But it also causes serious constellation diffusion and bit-error-rate (BER) under the multipath channel condition in traditional OFDM system. In order to reduce the constellation diffusion problem, a novel system which adds a pair of FFT/IFFT transform before the received signal direct expanding at the receiving terminal was proposed. While between the FFT and IFFT transform, frequency equilibrium will be used to eliminate multipath interference. Numerical results show that the BER performance of our proposed system is significantly lower than that of conventional OFDM systems.