KLT-based PAPR reduction technique for LTE-Advanced uplink with carrier aggregation

In LTE-Advanced, carrier aggregation (CA) allows the extension of the bandwidth allocated to a certain user up to 100 MHz. In particular, the NxSC-FDMA has been selected as the uplink extension scheme. However, one of the main practical challenges that comes with CA is the severe increase in the peak-to-average-power ratio (PAPR) of the aggregated time domain NxSC-FDMA signal. The PAPR increase is an important issue as it affects the efficiency of the power amplifier (PA) at the user equipment (UE) and equivalently the transmission coverage of the LTE-Advanced system. In this paper we propose a PAPR reduction technique based on the well-known Karhunen-Loeve Transform (KLT) to reduce the PAPR of the NxSC-FDMA signals. Several CA scenarios were analyzed using the proposed technique and simulation results show that the performance of the PAPR has improved by 1.5 dB in case of carrier aggregation of two CCs.