STBC MIMO-OFDM peak-to-average power ratio reduction by cross-antenna rotation and inversion

Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) has become a promising candidate for high performance 4G broadband wireless communications. However, like OFDM, one main disadvantage of MIMO-OFDM is that the signals transmitted on different antennas might exhibit a prohibitively large peak-to-average power ratio (PAPR). We will show that the PAPR reduction for MIMO-OFDM needs a more efficient solution than applying existing schemes for OFDM systems separately on each antenna. Further, we suggest a scheme of cross-antenna rotation and inversion (CARI), which utilizes additional degrees of freedom by employing multiple antennas. Two suboptimal schemes, termed successive suboptimal CARI (SS-CARI) and random suboptimal (RS-CARI) show significant performance advantages and lower computational complexity compared to the concurrent selective mapping (SLM) scheme proposed in Y. -L. Lee et al. (2003).