Peak-to-Average Power Ratio (PAPR) Suppression Method Using SLM and DCT in Combination for OTFS Systems

The Orthogonal Time Frequency Space (OTFS) system, has brought new opportunities and challenges. However, the OTFS system is also troubled by the problem of high Peak-to-Average Power Ratio (PAPR). In this paper, the research mainly focuses on the problem of high PAPR in the OTFS system, and a joint DCT-SLM algorithm based on the OTFS system is proposed. This algorithm first uses the Discrete Cosine Transform (DCT) to replace the Inverse Symplectic Finite Fourier Transform (ISFFT) and the Heisenberg transform in the traditional OTFS system, which simplifies the modulation that originally required two steps into one step. Secondly, the Selected Mapping (SLM) algorithm is used to further reduce the PAPR of the OTFS system. The simulation results show that when the Complementary Cumulative Distribution Function (CCDF) of the PAPR drops to 10–<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> while keeping a similar Bit Error Rate (BER), the PAPR threshold can be reduced by about 1.5 to 1.8 dB.