PA-Efficiency-Aware Hybrid PAPR Reduction for F-OFDM Systems with ICA Based Blind Equalization

Filtered-orthogonal frequency division multiplexing (F-OFDM) is a promising candidate waveform for the fifth generation (5G) wireless communications because of its high flexibility and low out-of-band emission (OOBE). However, it suffers from dramatic peak-to-average-power ratio (PAPR), which is higher than that of OFDM and results in the power amplifier (PA) not working in the high-efficiency region. We propose a hybrid PAPR reduction scheme including precoding, time-domain selected mapping (TSLM) and companding techniques, for F-OFDM systems with independent component analysis (ICA) based blind channel equalization, which can achieve significant PAPR reduction over the previous work. Also, this is the first work to reduce PAPR while enabling the PA to work with the highest possible efficiency. The reciprocal of the hybrid PAPR reduction is embedded in the ambiguity elimination process of ICA, and therefore does not require any dedicated side information from the transmitter or any exclusive signal processing at the receiver, leading to a much higher spectral efficiency (SE) and lower computational complexity than the previous work. The bit error rate (BER) performance of the system with the proposed hybrid PAPR reduction scheme is shown to be close to the ideal case with perfect channel state information (CSI), while no side information and training sequence are required for PAPR reduction and channel estimation, thanks to the effectiveness of the ICA based blind channel equalization.