Performance Comparison of Clipped and Filtered OFDM/QAM and SC/APSK with BICM

We compare the performance of orthogonal frequency division multiplexing (OFDM) system with high-order quadrature amplitude modulation (QAM) and single-carrier (SC) system with amplitude-phase shift keying (APSK) in conjunction with practical bit-interleaved coded modulation (BICM) considering their peak to average power ratio (PAPR) property. BICM-OFDM with high-order QAM is commonly adopted in several recent high-speed wireless communications standards, whereas APSK in conjunction with single-carrier signaling is adopted in satellite communications due to its low PAPR property compared to OFDM systems. In order to make a fair comparison, SC system is implemented as a discrete Fourier transform (DFT) precoding of OFDM such that the spectral efficiency of the two schemes is identical. Furthermore, clipping and filtering (CAF) is applied to the two systems so as to compare them under the same PAPR constraint. Simulation results over a frequency-selective Rician fading channel indicate that if the fading is moderate, SC with APSK can achieve significant gain over OFDM with QAM at the cost of increasing transmitter/receiver complexity.