Complexity-Reduced Algorithm for Adaptive PAPR Reduction Method Using Null Space in MIMO Channel for MIMO-OFDM Signals

Abstract

We propose a computational complexity-reduced algorithm for an adaptive peak-to-average power ratio (PAPR) reduction method previously developed by members of our research group that uses the null space in a multiple-input multiple-output (MIMO) channel for MIMO-orthogonal frequency division multiplexing (OFDM) signals. The proposed algorithm is an extension of the peak cancellation (PC) signal-based method that has been mainly investigated for per-antenna PAPR reduction approaches. This method adds the PC signal, which is designed so that the out-of-band radiation is removed/reduced, directly to the time-domain transmission signal at each antenna. By introducing a constraint so that the PC signal is transmitted only to the null space in the MIMO channel, the proposed method achieves approximately the same throughput-vs.-PAPR performance as the original method while dramatically reducing the required computational cost.