Modified PTS with FECs for PAPR reduction in MIMO-OFDM system with different subcarriers

Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) systems have been proposed in the recent past for providing high-data rate services over wireless channels. When combined with space time coding it provides the advantages of space-time coding and OFDM, resulting in a spectrally efficient wideband communication system. However, MIMO-OFDM systems suffer with the problem of inherent high peak to average power ratio (PAPR) due to the intersymbol interference between the subcarriers. In this paper, a generalized framework for PAPR reduction for space-time coded OFDM systems based on modified PTS using forward error-correcting codes (FECs) such as Turbo codes and Golay codes are employed in the modified PTS radix FFT, where, the PAPR is jointly optimized in both the real and imaginary parts, separately multiplied with phase factors when dividing the subcarriers into 4 subgroups. The simulation results show that the combined FEC with modified PTS technique significantly provides better PAPR reduction with reduced computational complexity compared to original PTS technique in the MIMO-OFDM systems.