信号处理2025，Vol.41Issue(4)：638-646,9.DOI:10.12466/xhcl.2025.04.005
面向OTFS系统的扩频峰均比抑制
Spread Spectrum Peak-to-Average Power Ratio Suppression for OTFS System
摘要
Abstract
Orthogonal Time Frequency Space(OTFS)modulation technology is increasingly being applied in high-dynamic scenarios due to its adaptability to Doppler shifts and delay conditions.Although OTFS as a multicarrier modu-lation scheme demonstrates strong performance in high-mobility communication,it faces a significant challenge with its high Peak-to-Average Power Ratio(PAPR).High PAPR can lead to nonlinear distortion in OTFS signals,degrading sig-nal quality and adversely affecting the overall performance of communication systems.To effectively reduce the PAPR of OTFS system waveforms and enhance transmission performance,this study proposes a PAPR suppression scheme based on spreading techniques.Specifically,by employing soft spreading and direct sequence spreading in the delay-Doppler domain,OTFS information symbols are extended using the favorable autocorrelation and constant modulus properties of Zadoff-Chu(ZC)sequences,along with the strong autocorrelation of m-sequences.This approach signifi-cantly suppresses signal PAPR,reduces nonlinear distortion,and enhances system capacity.Through theoretical deriva-tion,this study further demonstrates that under Phase Shift Keying(PSK)modulation,the transmitted signal waveform exhibits higher PAPR when the number of OTFS symbols exceeds the spreading factor and is an integer power of two of the spreading factors.Simulation results show that,compared to the original OTFS system,the proposed spreading-based OTFS system offers substantial improvements in PAPR performance.In particular,the soft-spreading OTFS sys-tem based on Zadoff-Chu(ZC)sequences displays constant modulus characteristics in its transmitted signal,signifi-cantly reducing the linearity requirements for power amplifiers.Additionally,the direct sequence spreading scheme based on m-sequences achieves approximately an 8.5 dB improvement in the PAPR of the transmitted signal.The simula-tion results validate the accuracy of the theoretical analysis and indicate that the proposed spreading-based OTFS system enhances transmission performance.关键词
峰均比/Zadoff-Chu序列/正交时频空/直接序列扩频Key words
peak-to-average power ratio/Zadoff-Chu(ZC)sequence/orthogonal time frequency space/direct se-quence spread spectrum分类
信息技术与安全科学引用本文复制引用
宋强健,朱立东..面向OTFS系统的扩频峰均比抑制[J].信号处理,2025,41(4):638-646,9.基金项目
国家自然科学基金(62371098)The National Natural Science Foundation of China(62371098) （62371098）
