Sub-block Permutation for Peak-to-Average Power Ratio Reduction in MIMO-OFDM System

High peak-to-average power ratio (PAPR) is known as a major drawback of the MIMO-OFDM system. The high PAPR at the transmitter may force its amplifier into saturation and cause non-linear distortion due to non-linear devices. Also, it can increase the complexity of digital-to-analog converters. This paper proposes a PAPR reduction method for MIMO-OFDM system. The main idea is based on generating multiple candidate signals that carry the same information and transmitting the one with minimum PAPR. In the proposed method, the OFDM data blocks are partitioned into a number of disjoint sub-blocks. Then, the sub-blocks are appropriately permuted to generate different candidates for transmission. The advantage of the proposed method is joint PAPR reduction at all transmit antennas. The simulation results of the proposed method shows a performance improvement of 1.91 dB over PTS-based approaches for . In this paper, a version of the proposed method which has lower computational complexity compared to that of the PTS-based approaches is also proposed. This version can reduce the computational complexity up to 99.7 %.