Time-frequency characteristics and PAPR reduction of OTDM waveform for 5G and beyond

This paper provides an in-depth investigation and analysis on the characteristics of channel-based transform waveforms and their differences from Fourier transform-based waveforms. Particularly, the basis functions of the recently proposed orthogonal transform division multiplexing (OTDM) waveform, which belongs to the category of channel-based transform waveforms, are comprehensively compared with the fixed exponential basis functions of orthogonal frequency division multiplexing (OFDM) waveform, which pertains to the class of Fourier transform-based waveforms. The obtained results show significant differences in the time and frequency characteristics of both classes of the waveforms. Also, the peak-to-average power ratio (PAPR) of OTDM is investigated and compared to OFDM. Then, a new effective technique, referred to as OTDM with edge subcarrier dedication (OTDM-ESD), is proposed for PAPR reduction by exploiting the special characteristics of the effective channel response in OTDM waveform. Simulation results show that the proposed OTDM-ESD technique not only reduces the PAPR, but also enhances the BER performance significantly.