Aggregating a lot of subcarriers will generate high peak-to-average power ratio (PAPR) which makes the overall system performance degradation. Among the existing PAPR reduction methods for orthogonal frequency-division multiplexing (OFDM)-based systems, iterative clipping and filtering (ICF) may be easy to implement, but ICF may cause signal distortion, so that the system cannot approximate the processed signals to the original signals which degrades error rates at receivers. Here, the authors proposed a new method based on ICF with smoothed clipping signals, and find the optimised filter to achieve the minimum error vector magnitude and efficiently reduce PAPR. Owing to the lack of a wide range of continuous bandwidth, the Third Generation Partnership Project proposed carrier aggregation (CA) technology in LTE-advanced systems. CA can aggregate many contiguous or non-contiguous fragment spectrums for supporting larger bandwidth and higher peak data rate. Here, the authors also evaluate the developed PAPR reduction scheme for the use in CA scenarios. The efficacy of the proposed scheme is demonstrated in the simulation results.