PAPR Reduction Methods for Eigenmode MIMO-OFDM Transmission

This paper proposes methods that can reduce peak- to-average power ratio (PAPR) while maintaining performance improvement by linear precoding for the eigenmode MIMO- OFDM transmission. In the eigenmode MIMO-OFDM system, a transmitter performs linear precoding using channel state information (CSI), and thus excellent transmission performance can be achieved. However, the transmitted signal still has high PAPR because of OFDM characteristics. To reduce such PAPR, this paper enhances selected mapping (SLM) and partial transmit sequence (PTS) which are known as PAPR reduction methods for OFDM. The enhanced methods, which are referred to as eigenmode transmission SLM (EM-SLM) and eigenmode transmission PTS (EM-PTS), can be applied to the eigenmode MIMO- OFDM without any performance degradation. Computer simulations demonstrate that in 4times4 MIMO-OFDM, the proposed methods can drastically reduce PAPR, and thus they can alleviate performance degradation due to nonlinear amplification.