Low-Complexity PAPR Reduction in DZT-OTFS System Through Clipping and Logarithmic Rooting Companding

Orthogonal time frequency space (OTFS) is an emerging multi-carrier modulation technique to mitigate large Doppler frequency shift in ultra-high-speed mobile communication environments. Implementation of traditional OTFS mainly relies on inverse symplectic finite Fourier transform (ISFFT) and Heisenberg transform (HT), and has high complexity. This paper adopts a low-complexity implementation using the discrete Zak transform (DZT). However, DZT-OTFS system still exhibits high peak-to-average power ratio (PAPR), which can drive OTFS signal into the nonlinear region of power amplifier. To address this problem, we propose a novel PAPR reduction method for DZT-OTFS system based on clipping and logarithmic rooting companding (CLRC). Theoretical analysis and simulation results demonstrate that this method significantly reduces PAPR value with mild bit error rate (BER) performance loss and maintaining low computational complexity compared with traditional simple clipping and filtering (SCF), clipping noise and filtering (CNF) and μ companding algorithms.