Abstract: Orthogonal time frequency space ( OTFS) modulation has an excellent performance in high-speed mobile scenarios. However, OTFS modulation is susceptible to the problem of high peak-to-average power ratio (PAPR). Regarding this issue, a selective mapping (SLM)method without transmitting side information is proposed to reduce the PAPR of OTFS signals. The random phase sequences are employed to scramble the transmitted symbols in the delay-Doppler ( DD) domain, and the unique degree of freedom of OTFS pulse pilot positions are used to carry the side information, which can be extracted by detecting the differences in the energy distribution of received symbols in the DD domain. Finally, the input-output relationship in the DD domain was derived again, and an improved channel estimation and signal detection algorithm was provided. Simulation results show that the proposed method can effectively reduce the PAPR by about 2.4 dB, and the performance loss of bit error rate is only 0.4 dB with the estimated channel state information.

Key words: orthogonal time frequency space modulation, peak-to-average power ratio, selective mapping, side information