PAPR Reduction via Degree of Freedom from Multiple Antennas in Large-Scale MIMO-OFDM Systems

Due to the high spectral efficiency and robustness against frequency-selective fading channels, large-scale multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) has become a promising technology for 5G communication systems. However, large-scale MIMO-OFDM is also faced with the problem of high peak-to-average power ratio (PAPR) caused by multicarrier signals. In this paper, an algorithm, which uses the degree of freedom provided by massive antenna arrays, is proposed to reduce the PAPR in large-scale MIMO-OFDM systems. The proposed algorithm, constructing a PAPR reduction signal in the null space of channel matrix, exhibits good PAPR reduction performance. To reduce the complexity, a suboptimal algorithm is also presented. Simulation results verify the advantages of the proposed algorithms.