Low-Complexity PTS-Based Schemes for PAPR Reduction in SFBC MIMO-OFDM Systems

Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) is an attractive technique for high-data-rate transmission. However, MIMO-OFDM systems have an inherent drawback in that the transmitted signals may suffer from a high peak-to-average power ratio (PAPR). The conventional partial transmit sequences (PTS) scheme can be applied to each transmitting antenna directly to reduce the PAPR of MIMO-OFDM systems, but it has high computational complexity. In this paper, two types of low-complexity PTS schemes are proposed to reduce the PAPR for MIMO-OFDM systems that use space-frequency block coding (SFBC). The two proposed PTS schemes use the sample powers of subblocks to generate cost functions for selecting samples to estimate the peak power of each candidate signal, thus reducing the computational complexity. In addition, for one of the proposed PTS schemes, the similarity of the input signals from the various transmitting antennas is used to further reduce the computational complexity. Simulation results show that, as compared with other related works, the proposed PTS schemes can achieve a reduced PAPR performance and a bit error rate performance close to that of SFBC MIMO-OFDM systems, but at much lower computational cost.