A Cross-domain PAPR Reduction Method for OTFS Modulation

In this work, a cross-domain PAPR reduction scheme is proposed, which is a combination of the phase rotation in the Delay-Doppler (DD) domain and the iterative clipping filtering (ICF) in the time domain. The former technique is distortion-less to the signals while incurring additional signaling overhead between the transceivers. The latter technique is more effective for PAPR reduction, but it can cause increased signal detection errors. Therefore, by leveraging the advantages of the two techniques, the proposed scheme can achieve improved PAPR reduction, given a trade-off between the signaling overhead and the bit error rate (BER). Specifically, the phase-rotation vectors optimization problem in the DD domain is formulated, and an iterative algorithm based on successive convex approximation (SCA) method and penalty convex-concave procedure (PCCP) is employed to solve this non-convex problem. Considering the phase quantization and signaling overhead in practical systems, a low-overhead group randomization algorithm is proposed to select the phase mapping in the grouped phase rotation stage, while the linear filtering is applied in the ICF stage, which can flexibly adjust the signaling overhead and the BER. Compared to the existing methods, numerical simulations justify the advantages of the proposed scheme, which further reduces 1-3 dB PAPR, while causing a lower BER.