PAPR Reduction Utilizing Difference in Singular Values Among Spatial Channels in Uplink Eigenmode Massive MIMO Transmission

In this paper, we propose a peak-to-average power ratio (PAPR) reduction method that utilizes the difference in singular values among spatial channels in uplink eigenmode massive multiple-input multiple-output (MIMO) transmission. The conventional method, clipping and filtering (CF), has a high capacity to reduce the PAPR. However, the in-band PAPR reduction signal in the CF process causes interference and deteriorates the data transmission performance. On the other hand, the proposed method assumes eigenmode MIMO transmission. This transmission produces a difference in singular values among spatial channels. Spatial channels with large singular values dominantly determine the data transmission quality but are susceptible to interference. In the proposed method, the in-band PAPR reduction signals are concentrated on spatial channels that have relatively small singular values. Simulations show that by protecting the spatial channels with high singular values from the PAPR reduction process, the proposed method significantly improves the transmission performance compared to that for the conventional method assuming the same level of PAPR reduction.