A stochastic optimization technique for PAPR reduction in the uplink of LTE-Advanced with carrier aggregation

The ever increase in the demand on peak data rates due to emerging services and applications has motivated the use of carrier aggregation (CA) as a key enabling technique to increase the bandwidth of users. CA allows the users to utilize both licensed and unlicensed spectrum simultaneously. 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 N×SC-FDMA signal. This issue affects the efficiency of the power amplifier (PA) at the user equipment (UE) in the uplink and hence the transmission coverage is reduced. In this paper, we propose a stochastic optimization technique to reduce the PAPR of N×SC-FDMA signals. Several CA scenarios were analyzed where experimental results show that the proposed technique outperforms the random circular shifting technique and can provide an average coverage gain of 40% for the case of 2 CCs.