ANovel Waveform with 1+D Filter Scheme for THz Communications

Terahertz (THz) communications are envisioned as a key scenario for the sixth-generation (6G) wireless communication system, which however suffer from some challenges, such as high path loss, poor power amplifier (PA) efficiency and high phase noise (PN). Low peak-to-average power ratio (PAPR) transmissions can alleviate the poor PA efficiency and improve the cell coverage. To support the low PAPR transmissions, pi/2 BPSK was introduced in the 3GPP 5G NR specifications and has now become mandatory. In addition to that, frequency domain spectrum shaping (FDSS) technique can be applied to the pi/2 BPSK modulation symbols to further reduce the PAPR, while occupies more spectrum resource. In this paper, we proposed a novel waveform based on enhanced discrete Fourier transform spread orthogonal frequency division multiplexing (E DFT-s-OFDM) waveform, in which the FDSS is replaced by the 1+D filtering process in the time domain. The 1+D filter has the characteristic of good time-frequency localization, so lower out-of-band leakage and less interference of the data part of the symbol to the tail sequence are achieved in E DFT-s-OFDM waveform. Compared with the DFT-s-OFDM waveform, the simulation results show that the novel waveform with 1+D filter scheme has lower PAPR, lower out-of-band leakage, and better phase noise estimation and compensation effect.