The Effect of Signal Distortion Techniques for PAPR Reduction on the BER Performance of LDPC and Turbo Coded OFDM System

Signal distortion techniques namely, peak windowing and clipping, are methods to address the high peak-to-average power ratio (PAPR) problem on OFDM systems. However, signal distortion technique introduces in-band and out-of-band distortion which may undermine the gain given by an error control code. This study investigated the effect of signal distortion techniques on the bit error rate (BER) performance of turbo and low density parity check (LDPC) coded orthogonal frequency division multiplexing (COFDM) communication system. It was found that LDPC-COFDM performs better than the turbo coded OFDM (T-COFDM) in an AWGN and exponentially decaying Rayleigh fade channel. Upon the application of signal distortion techniques, reduction in the coding gain was experienced by the LDPC-COFDM and T-COFDM. However, only a minimal loss was experienced by T-COFDM unlike the LDPC-COFDM. Thus, the effect of signal distortion to the T-COFDM system´s performance is a good trade off, considering the reduced PAPR level