MIMO-OFDM PAPR Reduction by Combining Shifting and Inversion with Matrix Transform

In this contribution, an optimal inter-antenna and subblock shifting and inversion (IAS SI) scheme exploiting additional degrees of freedom brought by multiple antennas and subblocks is proposed to alleviate peak-to-average power ratio (PAPR) problem of MIMO-OFDM systems. In order to reduce the complexity of proposed scheme, two suboptimal schemes based on sequential search and transformation are presented. Besides, combination of IASSI and matrix transform is proposed, which takes advantage of low autocorrelation characteristic of constant amplitude zero autocorrelation (CAZAC) sequence to further reduce PAPR. Simulation results show that IASSI improves PAPR reduction performance compared with existing PAPR reduction scheme. And when combined with orthogonal matrix transform utilizing CAZAC sequence, further gain can be obtained. All these proposed methods provide flexible tradeoff between satisfied PAPR reduction performance and cost of implementation.