DFT Precoder Technique Combined with μ-Law Companding for PAPR Reduction in OFDM System

Transmitting high data rate is one of the benefits of the orthogonal frequency division multiplexing (OFDM). However, it undergoes high Peak-to-Average Power Ratio (PAPR) which degrades the system performance. To overcome high PAPR of the OFDM system, the mu-law companding technique is applied. This technique expands only small signals and is not able to compress the high peaks effectively. As a result, average power increases. In this paper, Discrete Fourier Transform (DFT) precoding technique is employed to the mu-law-based OFDM system to reduce further PAPR by converting a multicarrier OFDM into a single-carrier OFDM system. Moreover, it not only reduces PAPR but also minimizes the system complexity because it is a linear technique. Simulation results show how the DFT precoder-based mu-law companding technique realizes reduced PAPR and improved Bit Error Rate (BER) performance in comparison to Discrete Hartley Transform (DHT) precoding with a mu-law companded-based OFDM system.