Low-PAPR Spatial Modulation for SC-FDMA
Although spatial modulation (SM) presents an attractive multiple-input–multiple-output (MIMO) technique, it increases peak-to-average power ratio (PAPR) on all transmit antennas when applied directly to single-carrier frequency-division multiple access (SC-FDMA). Therefore, we propose an SM modification, which is called low-PAPR SM (LPSM), to preserve the low PAPR level of SC-FDMA and to achieve the benefits of SM. In addition, as the optimal maximum-likelihood detection (MLD) receiver has a very high computational complexity when applied to SC-FDMA system, we observed suboptimal receivers for SC-FDMA with LPSM. In addition to low-complexity linear receivers, we proposed and analyzed two receivers: near-MLD and improved minimum mean square error (iMMSE) receivers. The near-MLD receiver achieves performance very near to MLD with significantly lower complexity, whereas the iMMSE receiver presents a tradeoff between MLD and linear receivers in terms of performance and complexity.